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Document and Entity Information	9 Months Ended
Document and Entity Information	Sep. 30, 2018 shares
Document And Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	HESM
Entity Registrant Name	Hess Midstream Partners LP
Entity Central Index Key	0001619739
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Common Units
Document And Entity Information [Line Items]
Entity Units Outstanding	27,297,031
Subordinated Units
Document And Entity Information [Line Items]
Entity Units Outstanding	27,279,654

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 34.6	$ 47.2
Accounts receivable—affiliate:
From contracts with customers	65.4	58.5
Other receivables	0.1	1.3
Other current assets	5.1	4.4
Total current assets	105.2	111.4
Equity investments	67.3
Property, plant and equipment, net	2,630.5	2,520.5
Other noncurrent assets	2.4	3.2
Total assets	2,805.4	2,635.1
Liabilities
Accounts payable—trade	12.8	12.2
Accounts payable—affiliate	23.3	22.5
Accrued liabilities	70.2	32.7
Other current liabilities	5.5	7.0
Total current liabilities	111.8	74.4
Other noncurrent liabilities	6.0	5.4
Total liabilities	117.8	79.8
Partners' capital
General partner	14.9	14.8
Total Hess Midstream Partners LP partners' capital	519.3	520.8
Noncontrolling interest	2,168.3	2,034.5
Total partners' capital	2,687.6	2,555.3
Total liabilities and partners' capital	2,805.4	2,635.1
Common Unitholders - Public
Partners' capital
Common and subordinated unitholders	357.6	357.7
Common Unitholders - Affiliate
Partners' capital
Common and subordinated unitholders	40.2	40.5
Subordinated Unitholders - Affiliate
Partners' capital
Common and subordinated unitholders	$ 106.6	$ 107.8

CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Sep. 30, 2018	Dec. 31, 2017
Common Unitholders - Public
Common and subordinated units issued	17,014,377	16,997,000
Common and subordinated units outstanding	17,014,377	16,997,000
Common Unitholders - Affiliate
Common and subordinated units issued	10,282,654	10,282,654
Common and subordinated units outstanding	10,282,654	10,282,654
Subordinated Unitholders - Affiliate
Common and subordinated units issued	27,279,654	27,279,654
Common and subordinated units outstanding	27,279,654	27,279,654

CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($)
shares in Millions, $ in Millions

3 Months Ended

9 Months Ended

Sep. 30, 2018

Sep. 30, 2017

Sep. 30, 2018

Sep. 30, 2017

Revenues

Affiliate services

$ 169.3

$ 146.7

$ 490.6

$ 415.3

Type of Revenue [Extensible List]

hesm:AffiliateServicesMember

Other income

$ 0.2

$ 0.6

Total revenues

169.5

$ 146.7

491.2

$ 415.3

Costs and expenses

Operating and maintenance expenses (exclusive of depreciation shown separately below)

39.4

39.6

111.1

117.3

Depreciation expense

30.6

28.5

90.8

83.8

General and administrative expenses

2.4

1.7

7.9

5.6

Total costs and expenses

72.4

69.8

209.8

206.7

Income from operations

97.1

76.9

281.4

208.6

Interest expense, net

0.3

0.4

1.0

0.9

Net income

96.8

76.5

280.4

207.7

Less: Net income attributable to noncontrolling interest

78.0

61.5

226.8

113.1

Net income attributable to Hess Midstream Partners LP

18.8

15.0

53.6

26.4

Less: General partner's interest in net income attributable to Hess Midstream Partners LP

0.5

0.3

1.2

0.5

Limited partners' interest in net income attributable to Hess Midstream Partners LP

$ 18.3

$ 14.7

$ 52.4

$ 25.9

Cash distributions declared per unit

^[1]

$ 0.3575

$ 0.3107

$ 1.0360

$ 0.5810

Predecessor

Costs and expenses

Net income

$ 68.2

Common Units

Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

$ 0.34

$ 0.27

$ 0.96

$ 0.48

Weighted average limited partner units outstanding, Basic:

Units outstanding, Basic

27.3

26.7

Weighted average limited partner units outstanding, Diluted:

Units outstanding, Diluted

27.4

27.3

27.4

26.7

Subordinated Units

Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

$ 0.34

$ 0.27

$ 0.96

$ 0.48

Weighted average limited partner units outstanding, Basic:

Units outstanding, Basic

27.3

26.7

Weighted average limited partner units outstanding, Diluted:

Units outstanding, Diluted

27.3

26.7

[1]	Represents cash distributions declared during the month following the end of each respective quarterly period. See Note 13, Subsequent Event.

CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL (UNAUDITED) - USD ($) $ in Millions	Total	General Partner	Noncontrolling Interest	Net Parent Investment Predecessor	Common Unitholders - Public Limited Partners	Common Unitholders - Affiliate Limited Partners	Subordinated Unitholders - Affiliate Limited Partners
Balance, beginning of period (Predecessor) at Dec. 31, 2016	$ 2,238.4			$ 2,238.4
Net income \| Predecessor	68.2			68.2
Net income	207.7
Other contributions from parent, net, prior to the IPO on April 10, 2017 \| Predecessor	225.0			225.0
Contribution of net assets to Hess Midstream Partners LP \| Predecessor		$ 14.6	$ 2,025.2	$ (2,531.6)		$ 134.6	$ 357.2
IPO proceeds, net of underwriters' discounts	365.5				$ 365.5
Offering costs	(10.7)				(10.7)
Distribution of IPO proceeds	(349.5)					(95.7)	(253.8)
Net income subsequent to the IPO on April 10, 2017	139.5	0.5	113.1		8.1	4.9	12.9
Unit-based compensation	0.2				0.2
Distributions to unitholders	(15.1)	(0.3)			(4.6)	(2.8)	(7.4)
Distributions to noncontrolling interest	(170.7)		(170.7)
Contribution from noncontrolling interest	70.8		70.8
Balance, end of period at Sep. 30, 2017	2,561.6	14.8	2,038.4		358.5	41.0	108.9
Balance, beginning of period at Dec. 31, 2017	2,555.3	14.8	2,034.5		357.7	40.5	107.8
Net income	280.4	1.2	226.8		16.3	9.9	26.2
Unit-based compensation	0.7				0.7
Distributions to unitholders	(55.8)	(1.1)			(17.1)	(10.2)	(27.4)
Distributions to noncontrolling interest	(149.2)		(149.2)
Contribution from noncontrolling interest	56.2		56.2
Balance, end of period at Sep. 30, 2018	$ 2,687.6	$ 14.9	$ 2,168.3		$ 357.6	$ 40.2	$ 106.6

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 280.4	$ 207.7
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense	90.8	83.8
Amortization of deferred financing costs	0.8	0.4
Unit-based compensation expense	0.7	0.2
Changes in assets and liabilities:
Accounts receivable – affiliate	(5.7)	(15.1)
Other current and noncurrent assets	(0.7)	1.9
Accounts payable – trade	0.6	(21.2)
Accounts payable – affiliate	0.8	23.5
Accrued liabilities	2.5	(3.1)
Other current and noncurrent liabilities	(2.8)	0.9
Net cash provided by (used in) operating activities	367.4	279.0
Cash flows from investing activities
Payments for equity investments	(67.3)
Additions to property, plant and equipment	(163.9)	(98.1)
Net cash provided by (used in) investing activities	(231.2)	(98.1)
Cash flows from financing activities
Cash distributions to parent prior to the IPO on April 10, 2017		(95.3)
Cash contributions from parent prior to the IPO on April 10, 2017		67.1
IPO proceeds, net of underwriters' discounts		365.5
Cash offering costs		(2.1)
Distribution of IPO proceeds to Hess and GIP		(349.5)
Financing costs		(3.9)
Distributions to unitholders	(55.8)	(15.1)
Distributions to noncontrolling interest	(149.2)	(170.7)
Contributions from noncontrolling interest	56.2	70.8
Net cash provided by (used in) financing activities	(148.8)	(133.2)
Increase (decrease) in cash and cash equivalents	(12.6)	47.7
Cash and cash equivalents, beginning of period	47.2	0.3
Cash and cash equivalents, end of period	$ 34.6	48.0
Supplemental disclosure of non-cash investing and financing activities:
Contributions to settle accounts payable – affiliate		253.2
Removal of historical capitalized offering costs		$ 8.6

Description of Business	9 Months Ended
Description of Business	Sep. 30, 2018
Description Of Business [Abstract]
Description of Business	Note 1. Description of Business Hess Midstream Partners LP (the “Partnership”) is a fee‑based, growth oriented traditional master limited partnership formed by Hess Infrastructure Partners LP (“Hess Infrastructure Partners”), a midstream joint venture with a 50% ownership interest held by affiliates of Hess Corporation (collectively “Hess”) and a 50% ownership interest held by GIP II Blue Holding Partnership LP (“GIP”), to own, operate, develop and acquire a diverse set of midstream assets to provide services to Hess and third‑party customers. On April 10, 2017, the Partnership completed its initial public offering (“IPO”) of 16,997,000 common units, which included 2,217,000 common units issued pursuant to the exercise of the underwriters’ over‑allotment options, representing 30.5% limited partner interests in the Partnership at a price to the public of $23.00 per common unit. In connection with the Partnership’s IPO, Hess Infrastructure Partners contributed a 20% controlling economic interest in each of (i) Hess North Dakota Pipelines Operations LP (“Gathering Opco”), which owns crude oil and natural gas gathering pipelines and compressor stations in North Dakota, (ii) Hess TGP Operations LP (“HTGP Opco”) which owns the Tioga Gas Plant (“TGP”), a natural gas processing and fractionation plant, including a residue gas pipeline in North Dakota, and (iii) Hess North Dakota Export Logistics Operations LP (“Logistics Opco”), which owns a crude oil and natural gas liquids (“NGL”) rail loading facility, crude oil rail cars and a crude oil pipeline and truck receipt terminal in North Dakota, and a 100% ownership interest in Hess Mentor Storage Holdings LLC (“Mentor Storage Terminal”), which owns a propane storage cavern and related rail and truck loading and unloading and storage terminal in Minnesota, (collectively, the “Contributed Businesses”) to the Partnership. On January 25, 2018, we entered into a 50/50 joint venture with Targa Resources Corp. to construct a new 200 million standard cubic feet per day gas processing plant called Little Missouri Four (“LM4”). Our 50% interest in the joint venture is held through HTGP Opco, in which we own a 20% controlling economic interest and Hess Infrastructure Partners owns the remaining 80% economic interest. Targa Resources Corp. manages the construction of LM4 and will operate the plant. The terms “we,” “our” and “us” as used in this report refer to the Partnership, unless the context suggests otherwise. These terms are used for convenience only and are not intended as a precise description of any separate legal entity within the Partnership. The term “parent” refers to Hess Infrastructure Partners. Our assets and operations are organized into the following three segments: (1) gathering, (2) processing and storage and (3) terminaling and export (see Note 12, Segments).

Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	Note 2. Basis of Presentation Presentation. The consolidated financial statements included in this report reflect all normal and recurring adjustments which, in the opinion of management, are necessary for a fair presentation of our consolidated financial position at September 30, 2018 and December 31, 2017, the consolidated results of operations for the three and nine months ended September 30, 2018 and 2017, and consolidated cash flows for the nine months ended September 30, 2018 and 2017. The unaudited results of operations for the interim periods reported are not necessarily indicative of results to be expected for the full year. The consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted from these interim consolidated financial statements. These financial statements, therefore, should be read in conjunction with the financial statements and related notes included in the Partnership’s annual report on Form 10‑K for the year ended December 31, 2017. Consolidation. We consolidate the activities of Gathering Opco, HTGP Opco and Logistics Opco, which qualify as variable interest entities (“VIE”) under U.S. GAAP. We have concluded that we are the primary beneficiary of each VIE, as defined in the accounting standards, since we have the power through our general partner interests to direct those activities that most significantly impact the economic performance of the Contributed Businesses and have a right to receive benefits and an obligation to absorb losses that could potentially be significant. All financial statement activities associated with VIEs are captured within gathering, processing and storage, and terminaling and export segments (see Note 12, Segments). We reflect a noncontrolling interest representing the retained limited partner interest owned by Hess Infrastructure Partners in the Contributed Businesses in the consolidated financial statements of the Partnership. All intercompany transactions and balances within the Partnership have been eliminated. Equity Investments. We account for our investment in LM4 under the equity method of accounting, as we do not control, but have a significant influence over, its operations. As of September 30, 2018, we have contributed $67.3 million of cash for our gross interest in LM4. We do not have a basis difference between the amount at which the investment is carried and the amount of underlying equity in net assets of the investee. Income Taxes. We are not a separate taxable entity for U.S. Federal and state income tax purposes; therefore, we do not provide for income tax benefit or expense. Each partner is subject to income taxes on its share of the Partnership’s earnings. Comprehensive Income. We have not reported comprehensive income, since there were no items of other comprehensive income during the periods presented in this report. Summary of Significant Accounting Policies In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) 2014‑09, Revenue from Contracts with Customers, as a new Accounting Standards Codification (ASC) Topic, ASC 606. We adopted ASC 606 as of January 1, 2018 using the modified retrospective method that requires application of the new standard prospectively from the date of adoption. The adoption of ASC 606 did not have a material impact on the timing or amount of revenue recognition for our uncompleted contracts at January 1, 2018 based on the requirements of the standard and, as a result, no cumulative effect adjustment was required to be recorded to our partners’ capital balance as of January 1, 2018. Accounts receivable from contracts with customers are presented separately in the consolidated balance sheet with the prior year balance recast to conform to the current period presentation. Revenue Recognition—Contracts with Customers. We earn substantially all of our revenues by charging fees for gathering, compressing and processing natural gas and fractionating NGLs; gathering, terminaling, loading and transporting crude oil and NGLs, and storing and terminaling propane. We do not own or take title to the volumes that we handle. Effective January 1, 2014, we entered into i) gas gathering, ii) crude oil gathering, iii) gas processing and fractionation, iv) storage services, and v) terminal and export services fee‑based commercial agreements with certain subsidiaries of Hess. Our responsibilities to provide each of the above services under each of the commercial agreements are considered separate, distinct performance obligations. We recognize revenues for each performance obligation under our commercial agreements over‑time as services are rendered using the output method, measured using the amount of volumes serviced during the period. The minimum volume commitments are subject to fluctuation based on nominations covering substantially all of Hess’s production and projected third-party volumes that will be purchased in the Bakken. As the minimum volume commitments are subject to fluctuation, and these commercial agreements contain fee inflation escalators and fee recalculation mechanisms, substantially all of the transaction price, as this term is defined in ASC 606, is variable at inception of each of the commercial agreements. As the variability is resolved prior to the recognition of revenue, we do not apply a constraint to the transaction price at the inception of the commercial agreements. We elected the practical expedient to recognize revenue in the amount to which we have a right to invoice as permitted under ASC 606. Due to this election and as the transaction price allocated to our unsatisfied performance obligations is entirely variable, we have elected the exemption provided by ASC 606 from the disclosure of revenue recognizable in future periods as our unsatisfied performance obligations are fulfilled. There are no significant financing components in any of our commercial agreements. The minimum volumes that Hess provides to our assets under our commercial agreements include dedicated production covering substantially all of Hess’s existing and future owned or controlled production in the Bakken and projected third-party volumes owned or controlled by Hess through dedicated third-party contracts. If Hess delivers volumes less than the applicable minimum volume commitments under our commercial agreements during any quarter, Hess is obligated to pay us a shortfall fee equal to the volume deficiency multiplied by the related gathering, processing and/or terminaling fee, as applicable. Our responsibility to stand-ready to service a minimum volume over each quarterly commitment period represents a separate, distinct performance obligation. Currently, and for the remainder of the Initial Term of each commercial agreement as described in Note 3 below, volume deficiencies are measured quarterly and recognized as revenue in the same period, as any associated shortfall payments are not subject to future reduction or offset. During the Secondary Term of each commercial agreement as described in Note 3 below, Hess will be entitled to receive a credit, calculated in barrels or Mcf, as applicable, with respect to the amount of any shortfall fee paid by Hess, which will initially be reported in deferred revenue. Hess may apply such credit against the fees payable for any volumes delivered to us under the applicable agreement in excess of Hess’ nominated volumes up to four quarters after such credit is earned. Unused credits by Hess will be recognized as revenue when they expire after four quarters. However, Hess will not be entitled to receive any such credit with respect to crude oil terminaling services under our terminal and export services agreement. Our revenues also include pass‑through third‑party rail transportation costs and electricity fees for which we recognize revenues in an amount equal to the costs. Refer to Note 12, Segments, for the presentation of our revenues on a disaggregated basis. All Affiliate services revenue which reflects activity associated with our commercial agreements with Hess, represents revenue from contracts with customers under the scope of ASC 606. Accounts Receivable. We record affiliate accounts receivable upon performance of services to affiliated companies. Generally, we receive payments from affiliated companies on a monthly basis, shortly after performance of services. There were no doubtful accounts written off, nor have we provided an allowance for doubtful accounts, as of September 30, 2018 and December 31, 2017. New Accounting Pronouncements In February 2016, the FASB issued ASU 2016‑02, Leases, as a new ASC Topic, ASC 842. The new standard supersedes ASC 840 and will require the recognition of right-of-use assets and lease liabilities for all leases with lease terms greater than one year, including leases currently treated as operating leases under ASC 840. ASC 842 is effective for us beginning in the first quarter of 2019, with early adoption permitted. We have elected to adopt ASC 842 on January 1, 2019 using the modified retrospective method which allows application of the new standard prospectively from the date of adoption with a cumulative effect adjustment, if any, recorded to partners’ capital at the date of adoption. Accordingly, comparative financial statements for periods prior to the adoption date of ASC 842 will not be affected. In addition, we have elected to apply the ‘package’ of practical expedients allowing us to avoid reassessing whether existing contracts are (or contain) leases, whether the lease classification for existing leases would differ under ASC 842, and whether initial direct costs incurred for existing leases are capitalizable under ASC 842. Finally, we have elected to apply the practical expedient allowing us to avoid reassessing land easements that were not previously accounted for as leases under ASC 840. We have not elected the ‘hindsight’ practical expedient when determining lease term. As part of our ASC 842 implementation project, we continue to evaluate contracts, monitor standard setting activity, and evaluate our internal controls to comply with the accounting and disclosure requirements of ASC 842.

Related Party Transactions

9 Months Ended

Sep. 30, 2018

Related Party Transactions

Note 3. Related Party Transactions

Commercial Agreements

Effective January 1, 2014, we entered into i) gas gathering, ii) crude oil gathering, iii) gas processing and fractionation, iv) storage services, and v) terminal and export services fee‑based commercial agreements with certain subsidiaries of Hess. Under these commercial agreements, we provide gathering, compression, processing, fractionation, storage, terminaling, loading and transportation services to Hess, for which we receive a fee per barrel of crude oil, Mcf of natural gas, or Mcf equivalent of NGLs, as applicable, delivered during each month, and Hess is obligated to provide us with minimum volumes of crude oil, natural gas and NGLs. These agreements also include inflation escalators and fee recalculation mechanisms that allow fees to be adjusted annually.

On September 17, 2018, we amended and restated our gas gathering and gas processing and fractionation agreements with Hess to enable us to provide certain services to Hess in respect of volumes to be delivered to and processed at the LM4 plant. Effective January 1, 2019, Hess will pay us a combined processing fee per Mcf of natural gas, or Mcf equivalent of NGLs, as applicable, for aggregate volumes processed at LM4 and Tioga Gas Plant. Except with regard to a certain gathering sub-system as described below, each of our commercial agreements with Hess retains its initial 10‑year term (“Initial Term”) and we have the unilateral right to extend each commercial agreement for one additional 10‑year term (“Secondary Term”). The amended and restated gas gathering agreement also extends the Initial Term of the gathering agreement with respect to a certain gathering sub-system by 5 years to provide for a 15-year Initial Term and decreases the Secondary Term for that gathering sub-system by 5 years to provide for a 5-year Secondary Term. In addition, the fee recalculation mechanism continues to apply to the amended and restated agreements and, effective January 1, 2019, will incorporate the revenues received and expected to be received by Hess from sourcing third-party dedicated production in order to further align the interests of us and Hess in promoting the growth of third-party volumes on our Bakken assets.

For the three and nine months ended September 30, 2018 and 2017, approximately 100% of our revenues were attributable to our fee‑based commercial agreements with Hess, including revenues from third‑party volumes contracted with Hess and delivered to us under these agreements. Together with Hess, we are pursuing strategic relationships with third‑party producers and other midstream companies with operations in the Bakken in order to maximize our utilization rates.

During the three and nine months ended September 30, 2018, we earned $11.5 million and $40.9 million, respectively, of minimum volume shortfall fee payments (2017: $13.4 million and $48.5 million, respectively). In addition, during the three and nine months ended September 30, 2018, we recognized, as part of affiliate revenues, $4.5 million and $12.1 million, respectively, of reimbursements from Hess related to third‑party rail transportation costs (2017: $3.4 million and $13.4 million, respectively). Finally, during the three and nine months ended September 30, 2018, we recognized, as part of affiliate revenues, $6.7 million and $20.1 million, respectively, of reimbursements from Hess related to electricity fees (2017: $6.6 million and $18.3 million, respectively). The related third-party transportation costs and electricity fees were included in Operating and maintenance expenses in the accompanying unaudited consolidated statements of operations.

Omnibus and Employee Secondment Agreements

Under our omnibus and employee secondment agreements, Hess provides substantial operational and administrative services to us in support of our assets and operations. For the three and nine months ended September 30, 2018 and 2017, we had the following charges from Hess. The classification of these charges between operating and maintenance expenses and general and administrative expenses is based on the fundamental nature of the services being performed for our operations.

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
(in millions)
Operating and maintenance expenses	$	11.7	$	13.7	$	34.6	$	41.2
General and administrative expenses		1.7		1.4		4.9		4.3
Total	$	13.4	$	15.1	$	39.5	$	45.5

Contribution Agreement

Under our contribution, conveyance and assumption agreement, Hess Infrastructure Partners agreed to bear the cost of certain maintenance capital projects associated with the Contributed Businesses. During the nine months ended September 30, 2018, Hess Infrastructure Partners contributed $2.4 million to us related to the reimbursement for those maintenance capital projects (2017: $9.2 million).

Property, Plant and Equipment

9 Months Ended

Sep. 30, 2018

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

Note 4. Property, Plant and Equipment

Property, plant and equipment, at cost, is as follows:

	Estimated useful lives	September 30, 2018			December 31, 2017
(in millions, except for number of years)
Gathering assets
Pipelines	22 years	$	930.9		$	890.8
Compressors, pumping stations and terminals	22 to 25 years		555.8			535.5
Gas plant assets
Pipelines, pipes and valves	22 to 25 years		460.0			460.0
Equipment	12 to 30 years		428.2			428.2
Buildings	35 years		182.3			182.3
Processing and fractionation facilities	25 years		184.8			158.4
Logistics facilities and railcars	20 to 25 years		382.7			371.1
Storage facilities	20 to 25 years		19.5			19.5
Other	20 to 25 years		10.6			9.2
Construction-in-progress	N/A		170.1			69.5
Total property, plant and equipment, at cost			3,324.9			3,124.5
Accumulated depreciation			(694.4	)		(604.0	)
Property, plant and equipment, net		$	2,630.5		$	2,520.5

Accrued Liabilities

9 Months Ended

Sep. 30, 2018

Accrued Liabilities Current [Abstract]

Accrued Liabilities

Note 5. Accrued Liabilities

Accrued liabilities are as follows:

	September 30, 2018		December 31, 2017
(in millions)
Accrued capital expenditures	$	57.8	$	22.8
Other accruals		12.4		9.9
Total	$	70.2	$	32.7

Debt and Interest Expense	9 Months Ended
Debt and Interest Expense	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt and Interest Expense	Note 6. Debt and Interest Expense Revolving Credit Facility On March 15, 2017, we entered into a four‑year, $300.0 million senior secured revolving credit facility that became available to us upon the closing of the IPO on April 10, 2017. Borrowings on the credit facility generally bear interest at the London Interbank Offered Rate (LIBOR) plus an applicable margin of 1.275%. The interest rate is subject to adjustment based on the Partnership’s leverage ratio, which is calculated as total debt to Earnings before Interest, Taxes, Depreciation and Amortization (EBITDA) (as defined in the credit agreement). Facility fees accrue at 0.275% per annum and are paid quarterly. If the Partnership obtains credit ratings, pricing levels will be based on our credit ratings in effect from time to time. The Partnership is subject to customary covenants in the credit agreement, including a financial covenant that generally requires a leverage ratio of no more than 4.5 to 1.0 for the prior four fiscal quarters. As of September 30, 2018, the revolving credit facility remained undrawn. The credit facility is secured by first priority perfected liens on substantially all directly owned assets of the Partnership and its wholly‑owned subsidiaries, including equity interests in subsidiaries, subject to certain customary exclusions.

Distributions

9 Months Ended

Sep. 30, 2018

Distributions Made To Members Or Limited Partners [Abstract]

Distributions

Note 7. Distributions

Our partnership agreement requires that, within 45 days after the end of each quarter, we distribute all of our available cash to unitholders of record on the applicable record date. The following table details the distributions declared and/or paid for the periods presented:

Period	Record Date	Distribution Date	Distribution per Common and Subordinated Unit
Second Quarter 2017⁽¹⁾	August 4, 2017	August 14, 2017	$	0.2703
Third Quarter 2017	November 3, 2017	November 13, 2017	$	0.3107
Fourth Quarter 2017	February 2, 2018	February 13, 2018	$	0.3218
First Quarter 2018	May 4, 2018	May 14, 2018	$	0.3333
Second Quarter 2018	August 2, 2018	August 13, 2018	$	0.3452
Third Quarter 2018⁽²⁾	November 5, 2018	November 13, 2018	$	0.3575

⁽¹⁾ The distribution for the second quarter 2017 was prorated from the closing of the Partnership’s IPO on April 10, 2017 and equated to a minimum quarterly distribution of $0.3000 per unit on a full quarter basis.

⁽²⁾ For more information, see Note 13, Subsequent Event.

Unit-Based Compensation

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Unit-Based Compensation

Note 8. Unit‑Based Compensation

In 2017, the Partnership adopted the Hess Midstream Partners LP 2017 Long‑Term Incentive Plan (the “LTIP”). Awards under the LTIP are available for officers, directors and employees of our general partner or its affiliates, and any individuals who perform services for the Partnership. The LTIP provides the Partnership with the flexibility to grant unit awards, restricted units, phantom units, unit options, unit appreciation rights, distribution equivalent rights, profits interest units and other unit‑based awards. The LTIP initially limits the number of common units that may be delivered pursuant to vested awards to 3,000,000 common units.

Under the LTIP, we granted awards of phantom units with distribution equivalent rights to certain officers, employees and directors. These phantom units and distribution equivalent rights vest ratably over a three‑year period for officers and employees, and vest after one year for directors. Cash distributions on the phantom units accumulate and are paid upon vesting. Fair value of phantom units is based on the fair value of the Partnership’s common units on the grant date.

Unit‑based award activity for the nine months ended September 30, 2018 was as follows:

				Weighted Average
				Award Date
	Number of Units			Fair Value
Outstanding and unvested units at December 31, 2017		44,127		$	22.85
Granted		90,594			20.51
Forfeited		(3,107	)		21.73
Vested		(17,377	)		22.63
Outstanding and unvested units at September 30, 2018		114,237		$	21.06

As of September 30, 2018, $1.8 million of compensation cost related to unvested phantom units awarded under the LTIP remains to be recognized over an expected weighted‑average period of 2.1 years.

Net Income per Limited Partner Unit

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Net Income per Limited Partner Unit

Note 9. Net Income per Limited Partner Unit

Net income per limited partner unit is computed by dividing the respective limited partners’ interest in net income attributable to Hess Midstream Partners LP by the weighted average number of common and subordinated units outstanding. Because we have more than one class of participating securities, we use the two‑class method when calculating net income per limited partner unit. The classes of participating securities include common units, subordinated units, general partner units and incentive distribution rights.

The following table illustrates the Partnership’s calculation of net income per limited partner unit:

	Three Months Ended September 30,				Nine Months Ended September 30,
(in millions, except per unit amounts)	2018		2017		2018		2017
Net income	$	96.8	$	76.5	$	280.4	$	207.7
Less: Net income prior to the IPO on April 10, 2017		-		-		-		68.2
Less: Net income attributable to noncontrolling interest		78.0		61.5		226.8		113.1
Net income attributable to Hess Midstream Partners LP		18.8		15.0		53.6		26.4
Less: General partner's interest in net income attributable to Hess Midstream Partners LP		0.5		0.3		1.2		0.5
Limited partners' interest in net income attributable to Hess Midstream Partners LP	$	18.3	$	14.7	$	52.4	$	25.9
Common unitholders' interest in net income attributable to Hess Midstream Partners LP	$	9.2	$	7.4	$	26.2	$	13.0
Subordinated unitholders' interest in net income attributable to Hess Midstream Partners LP	$	9.1	$	7.3	$	26.2	$	12.9
Net income attributable to Hess Midstream Partners LP per limited partner unit:
Common (basic and diluted)	$	0.34	$	0.27	$	0.96	$	0.48
Subordinated (basic and diluted)	$	0.34	$	0.27	$	0.96	$	0.48
Weighted average number of limited partner units outstanding:
Basic:
Common		27.3		27.3		27.3		26.7
Subordinated		27.3		27.3		27.3		26.7
Diluted:
Common		27.4		27.3		27.4		26.7
Subordinated		27.3		27.3		27.3		26.7

Concentration of Credit Risk	9 Months Ended
Concentration of Credit Risk	Sep. 30, 2018
Risks And Uncertainties [Abstract]
Concentration of Credit Risk	Note 10. Concentration of Credit Risk Hess represented approximately 100% of our total revenues and accounts receivable for the three and nine months ended September 30, 2018 and 2017.

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 11. Commitments and Contingencies Environmental Contingencies The Partnership is subject to federal, state and local laws and regulations relating to the environment. As of September 30, 2018, our reserves for estimated remediation liabilities included in Accrued liabilities and Other noncurrent liabilities were $0.7 million and $2.3 million, respectively, compared with $1.0 million and $2.4 million, respectively, as of December 31, 2017. Legal Proceedings In the ordinary course of business, the Partnership is from time to time party to various judicial and administrative proceedings. We regularly assess the need for accounting recognition or disclosure of these contingencies. In the case of a known contingency, we accrue a liability when the loss is probable and the amount is reasonably estimable. If a range of amounts can be reasonably estimated and no amount within the range is a better estimate than any other amount, then the minimum of the range is accrued. As of September 30, 2018 and December 31, 2017, we did not have accrued liabilities for any legal contingencies. Based on currently available information, we believe it is remote that the outcome of known matters would have a material adverse impact on our financial condition, results of operations or cash flows.

Segments

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Segments

Note 12. Segments

Our operations are located in the United States and are organized into three reportable segments: (1) gathering, (2) processing and storage and (3) terminaling and export. Our reportable segments comprise the structure used by our Chief Operating Decision Maker (“CODM”) to make key operating decisions and assess performance. These segments are strategic business units with differing products and services. Our CODM evaluates the segments’ operating performance based on multiple measures including Adjusted EBITDA, defined as earnings before interest, income tax, depreciation and amortization, as further adjusted for other non‑cash, non‑recurring items, if applicable.

The following tables reflect certain financial data for each reportable segment:

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated Hess Midstream Partners LP
(in millions)
For the Three Months Ended September 30, 2018
Revenues and other income	$	82.6	$	65.2	$	21.7	$	-		$	169.5
Net income (loss)		49.9		39.6		8.3		(1.0	)		96.8
Net income (loss) attributable to Hess Midstream Partners LP		10.1		8.1		1.6		(1.0	)		18.8
Depreciation expense		15.6		11.0		4.0		-			30.6
Interest expense, net		-		-		-		0.3			0.3
Adjusted EBITDA		65.5		50.6		12.3		(0.7	)		127.7
Adjusted EBITDA attributable to Hess Midstream Partners LP		13.2		10.3		2.4		(0.7	)		25.2
Capital expenditures		79.4		0.5		1.1		-			81.0

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated Hess Midstream Partners LP
(in millions)
For the Three Months Ended September 30, 2017
Revenues and other income	$	72.1	$	58.5	$	16.1	$	-		$	146.7
Net income (loss)		41.5		32.0		3.8		(0.8	)		76.5
Net income (loss) attributable to Hess Midstream Partners LP		8.2		6.7		0.9		(0.8	)		15.0
Depreciation expense		13.8		10.9		3.8		-			28.5
Interest expense, net		-		-		-		0.4			0.4
Adjusted EBITDA		55.3		42.9		7.6		(0.4	)		105.4
Adjusted EBITDA attributable to Hess Midstream Partners LP		11.0		8.9		1.6		(0.4	)		21.1
Capital expenditures		13.1		5.4		7.2		-			25.7

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated Hess Midstream Partners LP
(in millions)
For the Nine Months Ended September 30, 2018
Revenues and other income	$	243.0	$	186.4	$	61.8	$	-		$	491.2
Net income (loss)		148.6		111.0		24.8		(4.0	)		280.4
Net income (loss) attributable to Hess Midstream Partners LP		29.8		22.8		5.0		(4.0	)		53.6
Depreciation expense		46.2		32.8		11.8		-			90.8
Interest expense, net		-		-		-		1.0			1.0
Adjusted EBITDA		194.8		143.8		36.6		(3.0	)		372.2
Adjusted EBITDA attributable to Hess Midstream Partners LP		38.9		29.4		7.4		(3.0	)		72.7
Capital expenditures		187.7		7.9		3.3		-			198.9

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated Hess Midstream Partners LP
(in millions)
For the Nine Months Ended September 30, 2017
Revenues and other income	$	198.8	$	167.4	$	49.1	$	-		$	415.3
Net income (loss)		110.4		90.9		8.7		(2.3	)		207.7
Net income (loss) attributable to Hess Midstream Partners LP		15.2		12.1		1.4		(2.3	)		26.4
Depreciation expense		39.9		32.7		11.2		-			83.8
Interest expense, net		-		-		-		0.9			0.9
Adjusted EBITDA		150.3		123.6		19.9		(1.4	)		292.4
Adjusted EBITDA attributable to Hess Midstream Partners LP		20.5		16.2		2.8		(1.4	)		38.1
Capital expenditures		41.1		10.5		18.2		-			69.8

Total assets for the reportable segments are as follows:


	September 30, 2018		December 31, 2017
(in millions)
Gathering	$	1,426.5	$	1,280.5
Processing and Storage		1,018.7		972.8
Terminaling and Export		322.8		330.8
Interest and Other		37.4		51.0
Total assets	$	2,805.4	$	2,635.1

Subsequent Event	9 Months Ended
Subsequent Event	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Event	PART I – FINANCIAL INFORMATION (CONT’D) HESS MIDSTREAM PARTNERS LP NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED) Note 13. Subsequent Event On October 25, 2018, the board of directors of our general partner declared a quarterly cash distribution of $0.3575 per common and subordinated unit for the quarter ended September 30, 2018, an increase of 15% compared with the quarter ended September 30, 2017. The distribution will be payable on November 13, 2018, to unitholders of record as of the close of business on November 5, 2018.

Basis of Presentation (Policies)	9 Months Ended
Basis of Presentation (Policies)	Sep. 30, 2018
Accounting Policies [Abstract]
Presentation	Presentation. The consolidated financial statements included in this report reflect all normal and recurring adjustments which, in the opinion of management, are necessary for a fair presentation of our consolidated financial position at September 30, 2018 and December 31, 2017, the consolidated results of operations for the three and nine months ended September 30, 2018 and 2017, and consolidated cash flows for the nine months ended September 30, 2018 and 2017. The unaudited results of operations for the interim periods reported are not necessarily indicative of results to be expected for the full year. The consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted from these interim consolidated financial statements. These financial statements, therefore, should be read in conjunction with the financial statements and related notes included in the Partnership’s annual report on Form 10‑K for the year ended December 31, 2017.
Consolidation	Consolidation. We consolidate the activities of Gathering Opco, HTGP Opco and Logistics Opco, which qualify as variable interest entities (“VIE”) under U.S. GAAP. We have concluded that we are the primary beneficiary of each VIE, as defined in the accounting standards, since we have the power through our general partner interests to direct those activities that most significantly impact the economic performance of the Contributed Businesses and have a right to receive benefits and an obligation to absorb losses that could potentially be significant. All financial statement activities associated with VIEs are captured within gathering, processing and storage, and terminaling and export segments (see Note 12, Segments). We reflect a noncontrolling interest representing the retained limited partner interest owned by Hess Infrastructure Partners in the Contributed Businesses in the consolidated financial statements of the Partnership. All intercompany transactions and balances within the Partnership have been eliminated.
Equity Investments	Equity Investments. We account for our investment in LM4 under the equity method of accounting, as we do not control, but have a significant influence over, its operations. As of September 30, 2018, we have contributed $67.3 million of cash for our gross interest in LM4. We do not have a basis difference between the amount at which the investment is carried and the amount of underlying equity in net assets of the investee.
Income Taxes	Income Taxes. We are not a separate taxable entity for U.S. Federal and state income tax purposes; therefore, we do not provide for income tax benefit or expense. Each partner is subject to income taxes on its share of the Partnership’s earnings.
Comprehensive Income	Comprehensive Income. We have not reported comprehensive income, since there were no items of other comprehensive income during the periods presented in this report.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) 2014‑09, Revenue from Contracts with Customers, as a new Accounting Standards Codification (ASC) Topic, ASC 606. We adopted ASC 606 as of January 1, 2018 using the modified retrospective method that requires application of the new standard prospectively from the date of adoption. The adoption of ASC 606 did not have a material impact on the timing or amount of revenue recognition for our uncompleted contracts at January 1, 2018 based on the requirements of the standard and, as a result, no cumulative effect adjustment was required to be recorded to our partners’ capital balance as of January 1, 2018. Accounts receivable from contracts with customers are presented separately in the consolidated balance sheet with the prior year balance recast to conform to the current period presentation.
Revenue Recognition	Revenue Recognition—Contracts with Customers. We earn substantially all of our revenues by charging fees for gathering, compressing and processing natural gas and fractionating NGLs; gathering, terminaling, loading and transporting crude oil and NGLs, and storing and terminaling propane. We do not own or take title to the volumes that we handle. Effective January 1, 2014, we entered into i) gas gathering, ii) crude oil gathering, iii) gas processing and fractionation, iv) storage services, and v) terminal and export services fee‑based commercial agreements with certain subsidiaries of Hess. Our responsibilities to provide each of the above services under each of the commercial agreements are considered separate, distinct performance obligations. We recognize revenues for each performance obligation under our commercial agreements over‑time as services are rendered using the output method, measured using the amount of volumes serviced during the period. The minimum volume commitments are subject to fluctuation based on nominations covering substantially all of Hess’s production and projected third-party volumes that will be purchased in the Bakken. As the minimum volume commitments are subject to fluctuation, and these commercial agreements contain fee inflation escalators and fee recalculation mechanisms, substantially all of the transaction price, as this term is defined in ASC 606, is variable at inception of each of the commercial agreements. As the variability is resolved prior to the recognition of revenue, we do not apply a constraint to the transaction price at the inception of the commercial agreements. We elected the practical expedient to recognize revenue in the amount to which we have a right to invoice as permitted under ASC 606. Due to this election and as the transaction price allocated to our unsatisfied performance obligations is entirely variable, we have elected the exemption provided by ASC 606 from the disclosure of revenue recognizable in future periods as our unsatisfied performance obligations are fulfilled. There are no significant financing components in any of our commercial agreements. The minimum volumes that Hess provides to our assets under our commercial agreements include dedicated production covering substantially all of Hess’s existing and future owned or controlled production in the Bakken and projected third-party volumes owned or controlled by Hess through dedicated third-party contracts. If Hess delivers volumes less than the applicable minimum volume commitments under our commercial agreements during any quarter, Hess is obligated to pay us a shortfall fee equal to the volume deficiency multiplied by the related gathering, processing and/or terminaling fee, as applicable. Our responsibility to stand-ready to service a minimum volume over each quarterly commitment period represents a separate, distinct performance obligation. Currently, and for the remainder of the Initial Term of each commercial agreement as described in Note 3 below, volume deficiencies are measured quarterly and recognized as revenue in the same period, as any associated shortfall payments are not subject to future reduction or offset. During the Secondary Term of each commercial agreement as described in Note 3 below, Hess will be entitled to receive a credit, calculated in barrels or Mcf, as applicable, with respect to the amount of any shortfall fee paid by Hess, which will initially be reported in deferred revenue. Hess may apply such credit against the fees payable for any volumes delivered to us under the applicable agreement in excess of Hess’ nominated volumes up to four quarters after such credit is earned. Unused credits by Hess will be recognized as revenue when they expire after four quarters. However, Hess will not be entitled to receive any such credit with respect to crude oil terminaling services under our terminal and export services agreement. Our revenues also include pass‑through third‑party rail transportation costs and electricity fees for which we recognize revenues in an amount equal to the costs. Refer to Note 12, Segments, for the presentation of our revenues on a disaggregated basis. All Affiliate services revenue which reflects activity associated with our commercial agreements with Hess, represents revenue from contracts with customers under the scope of ASC 606.
Accounts Receivable	Accounts Receivable. We record affiliate accounts receivable upon performance of services to affiliated companies. Generally, we receive payments from affiliated companies on a monthly basis, shortly after performance of services. There were no doubtful accounts written off, nor have we provided an allowance for doubtful accounts, as of September 30, 2018 and December 31, 2017.
New Accounting Pronouncements	New Accounting Pronouncements In February 2016, the FASB issued ASU 2016‑02, Leases, as a new ASC Topic, ASC 842. The new standard supersedes ASC 840 and will require the recognition of right-of-use assets and lease liabilities for all leases with lease terms greater than one year, including leases currently treated as operating leases under ASC 840. ASC 842 is effective for us beginning in the first quarter of 2019, with early adoption permitted. We have elected to adopt ASC 842 on January 1, 2019 using the modified retrospective method which allows application of the new standard prospectively from the date of adoption with a cumulative effect adjustment, if any, recorded to partners’ capital at the date of adoption. Accordingly, comparative financial statements for periods prior to the adoption date of ASC 842 will not be affected. In addition, we have elected to apply the ‘package’ of practical expedients allowing us to avoid reassessing whether existing contracts are (or contain) leases, whether the lease classification for existing leases would differ under ASC 842, and whether initial direct costs incurred for existing leases are capitalizable under ASC 842. Finally, we have elected to apply the practical expedient allowing us to avoid reassessing land easements that were not previously accounted for as leases under ASC 840. We have not elected the ‘hindsight’ practical expedient when determining lease term. As part of our ASC 842 implementation project, we continue to evaluate contracts, monitor standard setting activity, and evaluate our internal controls to comply with the accounting and disclosure requirements of ASC 842.

Related Party Transactions (Tables)

9 Months Ended

Sep. 30, 2018

Summary of Classification of Charges between Operating and Maintenance Expenses and General and Administrative Expenses

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
(in millions)
Operating and maintenance expenses	$	11.7	$	13.7	$	34.6	$	41.2
General and administrative expenses		1.7		1.4		4.9		4.3
Total	$	13.4	$	15.1	$	39.5	$	45.5

Property, Plant and Equipment (Tables)

9 Months Ended

Sep. 30, 2018

Property Plant And Equipment [Abstract]

Components of Property, Plant and Equipment

Property, plant and equipment, at cost, is as follows:

	Estimated useful lives	September 30, 2018			December 31, 2017
(in millions, except for number of years)
Gathering assets
Pipelines	22 years	$	930.9		$	890.8
Compressors, pumping stations and terminals	22 to 25 years		555.8			535.5
Gas plant assets
Pipelines, pipes and valves	22 to 25 years		460.0			460.0
Equipment	12 to 30 years		428.2			428.2
Buildings	35 years		182.3			182.3
Processing and fractionation facilities	25 years		184.8			158.4
Logistics facilities and railcars	20 to 25 years		382.7			371.1
Storage facilities	20 to 25 years		19.5			19.5
Other	20 to 25 years		10.6			9.2
Construction-in-progress	N/A		170.1			69.5
Total property, plant and equipment, at cost			3,324.9			3,124.5
Accumulated depreciation			(694.4	)		(604.0	)
Property, plant and equipment, net		$	2,630.5		$	2,520.5

Accrued Liabilities (Tables)

9 Months Ended

Sep. 30, 2018

Accrued Liabilities Current [Abstract]

Schedule of Accrued Liabilities

Accrued liabilities are as follows:

	September 30, 2018		December 31, 2017
(in millions)
Accrued capital expenditures	$	57.8	$	22.8
Other accruals		12.4		9.9
Total	$	70.2	$	32.7

Distributions - (Tables)

9 Months Ended

Sep. 30, 2018

Distributions Made To Members Or Limited Partners [Abstract]

Schedule of Distributions Declared and Paid

The following table details the distributions declared and/or paid for the periods presented:

Period	Record Date	Distribution Date	Distribution per Common and Subordinated Unit
Second Quarter 2017⁽¹⁾	August 4, 2017	August 14, 2017	$	0.2703
Third Quarter 2017	November 3, 2017	November 13, 2017	$	0.3107
Fourth Quarter 2017	February 2, 2018	February 13, 2018	$	0.3218
First Quarter 2018	May 4, 2018	May 14, 2018	$	0.3333
Second Quarter 2018	August 2, 2018	August 13, 2018	$	0.3452
Third Quarter 2018⁽²⁾	November 5, 2018	November 13, 2018	$	0.3575

⁽²⁾ For more information, see Note 13, Subsequent Event.

Unit-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Unit-based Award Activity

Unit‑based award activity for the nine months ended September 30, 2018 was as follows:

				Weighted Average
				Award Date
	Number of Units			Fair Value
Outstanding and unvested units at December 31, 2017		44,127		$	22.85
Granted		90,594			20.51
Forfeited		(3,107	)		21.73
Vested		(17,377	)		22.63
Outstanding and unvested units at September 30, 2018		114,237		$	21.06

Net Income per Limited Partner Unit (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Schedule of Net Income per Limited Partner Unit

The following table illustrates the Partnership’s calculation of net income per limited partner unit:

	Three Months Ended September 30,				Nine Months Ended September 30,
(in millions, except per unit amounts)	2018		2017		2018		2017
Net income	$	96.8	$	76.5	$	280.4	$	207.7
Less: Net income prior to the IPO on April 10, 2017		-		-		-		68.2
Less: Net income attributable to noncontrolling interest		78.0		61.5		226.8		113.1
Net income attributable to Hess Midstream Partners LP		18.8		15.0		53.6		26.4
Less: General partner's interest in net income attributable to Hess Midstream Partners LP		0.5		0.3		1.2		0.5
Limited partners' interest in net income attributable to Hess Midstream Partners LP	$	18.3	$	14.7	$	52.4	$	25.9
Common unitholders' interest in net income attributable to Hess Midstream Partners LP	$	9.2	$	7.4	$	26.2	$	13.0
Subordinated unitholders' interest in net income attributable to Hess Midstream Partners LP	$	9.1	$	7.3	$	26.2	$	12.9
Net income attributable to Hess Midstream Partners LP per limited partner unit:
Common (basic and diluted)	$	0.34	$	0.27	$	0.96	$	0.48
Subordinated (basic and diluted)	$	0.34	$	0.27	$	0.96	$	0.48
Weighted average number of limited partner units outstanding:
Basic:
Common		27.3		27.3		27.3		26.7
Subordinated		27.3		27.3		27.3		26.7
Diluted:
Common		27.4		27.3		27.4		26.7
Subordinated		27.3		27.3		27.3		26.7

Segments (Tables)

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Financial Data for Each Reportable Segment

The following tables reflect certain financial data for each reportable segment:

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated Hess Midstream Partners LP
(in millions)
For the Three Months Ended September 30, 2018
Revenues and other income	$	82.6	$	65.2	$	21.7	$	-		$	169.5
Net income (loss)		49.9		39.6		8.3		(1.0	)		96.8
Net income (loss) attributable to Hess Midstream Partners LP		10.1		8.1		1.6		(1.0	)		18.8
Depreciation expense		15.6		11.0		4.0		-			30.6
Interest expense, net		-		-		-		0.3			0.3
Adjusted EBITDA		65.5		50.6		12.3		(0.7	)		127.7
Adjusted EBITDA attributable to Hess Midstream Partners LP		13.2		10.3		2.4		(0.7	)		25.2
Capital expenditures		79.4		0.5		1.1		-			81.0

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated Hess Midstream Partners LP
(in millions)
For the Three Months Ended September 30, 2017
Revenues and other income	$	72.1	$	58.5	$	16.1	$	-		$	146.7
Net income (loss)		41.5		32.0		3.8		(0.8	)		76.5
Net income (loss) attributable to Hess Midstream Partners LP		8.2		6.7		0.9		(0.8	)		15.0
Depreciation expense		13.8		10.9		3.8		-			28.5
Interest expense, net		-		-		-		0.4			0.4
Adjusted EBITDA		55.3		42.9		7.6		(0.4	)		105.4
Adjusted EBITDA attributable to Hess Midstream Partners LP		11.0		8.9		1.6		(0.4	)		21.1
Capital expenditures		13.1		5.4		7.2		-			25.7

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated Hess Midstream Partners LP
(in millions)
For the Nine Months Ended September 30, 2018
Revenues and other income	$	243.0	$	186.4	$	61.8	$	-		$	491.2
Net income (loss)		148.6		111.0		24.8		(4.0	)		280.4
Net income (loss) attributable to Hess Midstream Partners LP		29.8		22.8		5.0		(4.0	)		53.6
Depreciation expense		46.2		32.8		11.8		-			90.8
Interest expense, net		-		-		-		1.0			1.0
Adjusted EBITDA		194.8		143.8		36.6		(3.0	)		372.2
Adjusted EBITDA attributable to Hess Midstream Partners LP		38.9		29.4		7.4		(3.0	)		72.7
Capital expenditures		187.7		7.9		3.3		-			198.9

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated Hess Midstream Partners LP
(in millions)
For the Nine Months Ended September 30, 2017
Revenues and other income	$	198.8	$	167.4	$	49.1	$	-		$	415.3
Net income (loss)		110.4		90.9		8.7		(2.3	)		207.7
Net income (loss) attributable to Hess Midstream Partners LP		15.2		12.1		1.4		(2.3	)		26.4
Depreciation expense		39.9		32.7		11.2		-			83.8
Interest expense, net		-		-		-		0.9			0.9
Adjusted EBITDA		150.3		123.6		19.9		(1.4	)		292.4
Adjusted EBITDA attributable to Hess Midstream Partners LP		20.5		16.2		2.8		(1.4	)		38.1
Capital expenditures		41.1		10.5		18.2		-			69.8

Total Assets for Reportable Segments

Total assets for the reportable segments are as follows:


	September 30, 2018		December 31, 2017
(in millions)
Gathering	$	1,426.5	$	1,280.5
Processing and Storage		1,018.7		972.8
Terminaling and Export		322.8		330.8
Interest and Other		37.4		51.0
Total assets	$	2,805.4	$	2,635.1

Description of Business - Additional Information (Detail)		9 Months Ended
	Apr. 10, 2017 $ / shares shares	Sep. 30, 2018 Segment	Jan. 25, 2018 MMcf
Description Of Business [Line Items]
Initial public offering, common units	16,997,000
Number of operating segments \| Segment		3
LM4
Description Of Business [Line Items]
Percentage of ownership in joint venture			50.00%
Gas processing plant capacity \| MMcf			200
Hess T G P Operations Limited Partnership
Description Of Business [Line Items]
Controlling economic interest percentage			20.00%
Hess T G P Operations Limited Partnership \| LM4
Description Of Business [Line Items]
Percentage of ownership in joint venture			50.00%
Targa Resources Corp. \| LM4
Description Of Business [Line Items]
Percentage of ownership in joint venture			50.00%
Over-Allotment Options
Description Of Business [Line Items]
Initial public offering, common units	2,217,000
Percentage of ownership interest	30.50%
Shares Issued, Price Per Share \| $ / shares	$ 23.00
Hess Infrastructure Partners LP \| IPO \| Gathering Opco
Description Of Business [Line Items]
Percentage of ownership interest	20.00%
Hess Infrastructure Partners LP \| IPO \| Hess T G P Operations Limited Partnership
Description Of Business [Line Items]
Percentage of ownership interest	20.00%
Hess Infrastructure Partners LP \| IPO \| Hess North Dakota Export Logistics Operations Limited Partnership
Description Of Business [Line Items]
Percentage of ownership interest	20.00%
Hess Infrastructure Partners LP \| IPO \| Hess Mentor Storage Holdings Limited Liability Company
Description Of Business [Line Items]
Percentage of ownership interest	100.00%
Hess Corporation
Description Of Business [Line Items]
Percentage of ownership in joint venture		50.00%
GIP II Blue Holding Partnership, LP
Description Of Business [Line Items]
Percentage of ownership in joint venture		50.00%
Hess Infrastructure Partners LP \| Hess T G P Operations Limited Partnership
Description Of Business [Line Items]
Controlling economic interest by the parent percentage			80.00%

Basis of Presentation - Additional Information (Detail) - USD ($)		9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Accounting Policies [Line Items]
Cash contributed to acquire equity method investments		$ 67,300,000
Doubtful accounts written off		0	$ 0
Allowance for doubtful accounts	$ 0	$ 0	$ 0
LM4
Accounting Policies [Line Items]
Cash contributed to acquire equity method investments	$ 67,300,000

Related Party Transactions - Additional Information (Detail) - USD ($)		3 Months Ended		9 Months Ended
	Sep. 17, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Related Party Transaction [Line Items]
Reimbursement revenue		$ 169,300,000	$ 146,700,000	$ 490,600,000	$ 415,300,000
Credit Concentration Risk \| Revenue
Related Party Transaction [Line Items]
Revenues attributable to fee based commercial agreements		100.00%	100.00%	100.00%	100.00%
Hess
Related Party Transaction [Line Items]
Minimum volume shortfall fee payments earned		$ 11,500,000	$ 13,400,000	$ 40,900,000	$ 48,500,000
Hess \| Rail Transportation Costs
Related Party Transaction [Line Items]
Reimbursement revenue		4,500,000	3,400,000	12,100,000	13,400,000
Hess \| Electricity Fees
Related Party Transaction [Line Items]
Reimbursement revenue		$ 6,700,000	$ 6,600,000	$ 20,100,000	$ 18,300,000
Hess \| Credit Concentration Risk \| Revenue
Related Party Transaction [Line Items]
Revenues attributable to fee based commercial agreements		100.00%	100.00%	100.00%	100.00%
Hess \| Amended and Restated Commercial Agreement
Related Party Transaction [Line Items]
Initial term of agreement	10 years
Agreement description				Each of our commercial agreements with Hess has an initial 10year term (“Initial Term”) and we have the unilateral right to extend each commercial agreement for one additional 10year term (“Secondary Term”).
Number of rights to extend the term of agreement	one
Secondary term of agreement	10 years
Hess \| Amended and Restated Agreement for Certain Gas Gathering Sub-system
Related Party Transaction [Line Items]
Initial term of agreement	15 years
Agreement description				The amended and restated gas gathering agreement also extends the Initial Term of the gathering agreement with respect to a certain gathering sub-system by 5 years to provide for a 15-year Initial Term and decreases the Secondary Term for that gathering sub-system by 5 years to provide for a 5-year Secondary Term.
Secondary term of agreement	5 years
Initial term to extend by period	5 years
Secondary term to reduce by period	5 years
Hess Infrastructure Partners LP \| Maintenance Capital Projects
Related Party Transaction [Line Items]
Reimbursement of maintenance expenses				$ 2,400,000	$ 9,200,000

Related Party Transactions - Summary of Classification of Charges between Operating and Maintenance Expenses and General and Administrative Expenses (Detail) - Hess - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Related Party Transaction [Line Items]
Operating and maintenance expenses	$ 11.7	$ 13.7	$ 34.6	$ 41.2
General and administrative expenses	1.7	1.4	4.9	4.3
Total	$ 13.4	$ 15.1	$ 39.5	$ 45.5

Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 3,324.9	$ 3,124.5
Accumulated depreciation	(694.4)	(604.0)
Property, plant and equipment, net	2,630.5	2,520.5
Logistics Facilities and Railcars
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	382.7	371.1
Storage Facilities
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	19.5	19.5
Other
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	10.6	9.2
Construction-In-Progress
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 170.1	69.5
Minimum \| Logistics Facilities and Railcars
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	20 years
Minimum \| Storage Facilities
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	20 years
Minimum \| Other
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	20 years
Maximum \| Logistics Facilities and Railcars
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Maximum \| Storage Facilities
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Maximum \| Other
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Gathering Assets \| Pipelines
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	22 years
Total property, plant and equipment, at cost	$ 930.9	890.8
Gathering Assets \| Compressors, Pumping Stations and Terminals
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 555.8	535.5
Gathering Assets \| Minimum \| Compressors, Pumping Stations and Terminals
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	22 years
Gathering Assets \| Maximum \| Compressors, Pumping Stations and Terminals
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Gas Plant Assets \| Pipelines, Pipes and Valves
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 460.0	460.0
Gas Plant Assets \| Equipment
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 428.2	428.2
Gas Plant Assets \| Buildings
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	35 years
Total property, plant and equipment, at cost	$ 182.3	182.3
Gas Plant Assets \| Processing and Fractionation Facilities
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Total property, plant and equipment, at cost	$ 184.8	$ 158.4
Gas Plant Assets \| Minimum \| Pipelines, Pipes and Valves
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	22 years
Gas Plant Assets \| Minimum \| Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	12 years
Gas Plant Assets \| Maximum \| Pipelines, Pipes and Valves
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Gas Plant Assets \| Maximum \| Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	30 years

Accrued Liabilities - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Accrued Liabilities Current [Abstract]
Accrued capital expenditures	$ 57.8	$ 22.8
Other accruals	12.4	9.9
Total	$ 70.2	$ 32.7

Debt and Interest Expense - Additional Information (Detail) - Senior Secured Revolving Credit Facility - USD ($)		9 Months Ended
	Mar. 15, 2017	Sep. 30, 2018
Debt Instrument [Line Items]
Revolving credit facility - Term	4 years
Maximum borrowing capacity	$ 300,000,000
Percentage of facility fees accrued per annum and paid quarterly	0.275%
Debt covenant, leverage ratio		450.00%
London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Interest rate, applicable margin	1.275%

Distributions - Additional Information (Detail)	9 Months Ended
Distributions - Additional Information (Detail)	Sep. 30, 2018
Distributions Made To Members Or Limited Partners [Abstract]
Period of cash distribution to unitholders	45 days

Distributions - Schedule of Distributions Declared and Paid (Detail) - $ / shares

3 Months Ended

9 Months Ended

Sep. 30, 2018

Sep. 30, 2017

Sep. 30, 2018

Sep. 30, 2017

Distribution Made To Limited Partner [Line Items]

Distribution per Common and Subordinated Unit

^[1]

$ 0.3575

$ 0.3107

$ 1.0360

$ 0.5810

Second Quarter 2017

Distribution Made To Limited Partner [Line Items]

Record Date

^[2]

Aug. 04, 2017

Distribution Date

^[2]

Aug. 14, 2017

Distribution per Common and Subordinated Unit

^[2]

$ 0.2703

Third Quarter 2017

Distribution Made To Limited Partner [Line Items]

Record Date

Nov. 03, 2017

Distribution Date

Nov. 13, 2017

Distribution per Common and Subordinated Unit

$ 0.3107

Fourth Quarter 2017

Distribution Made To Limited Partner [Line Items]

Record Date

Feb. 02, 2018

Distribution Date

Feb. 13, 2018

Distribution per Common and Subordinated Unit

$ 0.3218

First Quarter 2018

Distribution Made To Limited Partner [Line Items]

Record Date

May 04, 2018

Distribution Date

May 14, 2018

Distribution per Common and Subordinated Unit

$ 0.3333

Second Quarter 2018

Distribution Made To Limited Partner [Line Items]

Record Date

Aug. 02, 2018

Distribution Date

Aug. 13, 2018

Distribution per Common and Subordinated Unit

$ 0.3452

Third Quarter 2018

Distribution Made To Limited Partner [Line Items]

Record Date

^[3]

Nov. 05, 2018

Distribution Date

^[3]

Nov. 13, 2018

Distribution per Common and Subordinated Unit

^[3]

$ 0.3575

[1]	Represents cash distributions declared during the month following the end of each respective quarterly period. See Note 13, Subsequent Event.
[2]	The distribution for the second quarter 2017 was prorated from the closing of the Partnership’s IPO on April 10, 2017 and equated to a minimum quarterly distribution of $0.3000 per unit on a full quarter basis.
[3]	For more information, see Note 13, Subsequent Event.

Distributions - Schedule of Distributions Declared and Paid (Parenthetical) (Detail)	3 Months Ended
	Jun. 30, 2017 $ / shares
Distributions Made To Members Or Limited Partners [Abstract]
Minimum quarterly distribution per unit	$ 0.3000

Unit-Based Compensation - Additional Information (Detail) - 2017 Long-Term Incentive Plan $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($) shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Available common units pursuant to vested awards \| shares	3,000,000
Cost related to unvested phantom units to be recognized \| $	$ 1.8
Cost related to unvested phantom units to be recognized, over an expected weighted-average period	2 years 1 month 6 days
Officers and Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Phantom units vesting period	3 years
Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Phantom units vesting period	1 year

Unit-Based Compensation - Schedule of Unit-based Award Activity (Detail) - Phantom Units	9 Months Ended
	Sep. 30, 2018 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding and unvested units at December 31, 2017, Number of Units \| shares	44,127
Granted, Number of Units \| shares	90,594
Forfeited, Number of Units \| shares	(3,107)
Vested, Number of Units \| shares	(17,377)
Outstanding and unvested units at September 30, 2018, Number of Units \| shares	114,237
Outstanding and unvested units at December 31, 2017, Weighted Average Award Date Fair Value \| $ / shares	$ 22.85
Granted, Weighted Average Award Date Fair Value \| $ / shares	20.51
Forfeited, Weighted Average Award Date Fair Value \| $ / shares	21.73
Vested, Weighted Average Award Date Fair Value \| $ / shares	22.63
Outstanding and unvested units at September 30, 2018, Weighted Average Award Date Fair Value \| $ / shares	$ 21.06

Net Income per Limited Partner Unit - Partnership's Calculation of Net Income per Limited Partner Unit (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Limited Partners Capital Account [Line Items]
Net income	$ 96.8	$ 76.5	$ 280.4	$ 207.7
Less: Net income attributable to noncontrolling interest	78.0	61.5	226.8	113.1
Net income attributable to Hess Midstream Partners LP	18.8	15.0	53.6	26.4
Less: General partner's interest in net income attributable to Hess Midstream Partners LP	0.5	0.3	1.2	0.5
Limited partners' interest in net income attributable to Hess Midstream Partners LP	18.3	14.7	52.4	25.9
Predecessor
Limited Partners Capital Account [Line Items]
Net income				68.2
Common Units
Limited Partners Capital Account [Line Items]
Common unitholders' interest in net income attributable to Hess Midstream Partners LP	$ 9.2	$ 7.4	$ 26.2	$ 13.0
Net income attributable to Hess Midstream Partners LP per limited partner unit:
Basic and diluted	$ 0.34	$ 0.27	$ 0.96	$ 0.48
Weighted average limited partner units outstanding, Basic:
Units outstanding, Basic	27.3	27.3	27.3	26.7
Weighted average limited partner units outstanding, Diluted:
Units outstanding, Diluted	27.4	27.3	27.4	26.7
Subordinated Units
Limited Partners Capital Account [Line Items]
Common unitholders' interest in net income attributable to Hess Midstream Partners LP	$ 9.1	$ 7.3	$ 26.2	$ 12.9
Net income attributable to Hess Midstream Partners LP per limited partner unit:
Basic and diluted	$ 0.34	$ 0.27	$ 0.96	$ 0.48
Weighted average limited partner units outstanding, Basic:
Units outstanding, Basic	27.3	27.3	27.3	26.7
Weighted average limited partner units outstanding, Diluted:
Units outstanding, Diluted	27.3	27.3	27.3	26.7

Concentration of Credit Risk - Additional Information (Detail) - Credit Concentration Risk	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Estimated remediation liabilities included in accrued liabilities	$ 700,000	$ 1,000,000
Estimated remediation liabilities included in other noncurrent liabilities	2,300,000	2,400,000
Accrued liabilities for legal contingencies	$ 0	$ 0

Segments - Additional Information (Detail)	9 Months Ended
Segments - Additional Information (Detail)	Sep. 30, 2018 Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segments - Financial Data for Each Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Revenues and other income	$ 169.5	$ 146.7	$ 491.2	$ 415.3
Net income (loss)	96.8	76.5	280.4	207.7
Net income (loss) attributable to Hess Midstream Partners LP	18.8	15.0	53.6	26.4
Depreciation expense	30.6	28.5	90.8	83.8
Interest expense, net	0.3	0.4	1.0	0.9
Adjusted EBITDA	127.7	105.4	372.2	292.4
Adjusted EBITDA attributable to Hess Midstream Partners LP	25.2	21.1	72.7	38.1
Capital expenditures	81.0	25.7	198.9	69.8
Interest and Other
Segment Reporting Information [Line Items]
Net income (loss)	(1.0)	(0.8)	(4.0)	(2.3)
Net income (loss) attributable to Hess Midstream Partners LP	(1.0)	(0.8)	(4.0)	(2.3)
Interest expense, net	0.3	0.4	1.0	0.9
Adjusted EBITDA	(0.7)	(0.4)	(3.0)	(1.4)
Adjusted EBITDA attributable to Hess Midstream Partners LP	(0.7)	(0.4)	(3.0)	(1.4)
Gathering Opco \| Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	82.6	72.1	243.0	198.8
Net income (loss)	49.9	41.5	148.6	110.4
Net income (loss) attributable to Hess Midstream Partners LP	10.1	8.2	29.8	15.2
Depreciation expense	15.6	13.8	46.2	39.9
Adjusted EBITDA	65.5	55.3	194.8	150.3
Adjusted EBITDA attributable to Hess Midstream Partners LP	13.2	11.0	38.9	20.5
Capital expenditures	79.4	13.1	187.7	41.1
Processing and Storage \| Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	65.2	58.5	186.4	167.4
Net income (loss)	39.6	32.0	111.0	90.9
Net income (loss) attributable to Hess Midstream Partners LP	8.1	6.7	22.8	12.1
Depreciation expense	11.0	10.9	32.8	32.7
Adjusted EBITDA	50.6	42.9	143.8	123.6
Adjusted EBITDA attributable to Hess Midstream Partners LP	10.3	8.9	29.4	16.2
Capital expenditures	0.5	5.4	7.9	10.5
Terminaling and Export \| Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	21.7	16.1	61.8	49.1
Net income (loss)	8.3	3.8	24.8	8.7
Net income (loss) attributable to Hess Midstream Partners LP	1.6	0.9	5.0	1.4
Depreciation expense	4.0	3.8	11.8	11.2
Adjusted EBITDA	12.3	7.6	36.6	19.9
Adjusted EBITDA attributable to Hess Midstream Partners LP	2.4	1.6	7.4	2.8
Capital expenditures	$ 1.1	$ 7.2	$ 3.3	$ 18.2

Segments - Total Assets for Reportable Segments (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total assets	$ 2,805.4	$ 2,635.1
Interest and Other
Segment Reporting Information [Line Items]
Total assets	37.4	51.0
Gathering Opco \| Operating Segments
Segment Reporting Information [Line Items]
Total assets	1,426.5	1,280.5
Processing and Storage \| Operating Segments
Segment Reporting Information [Line Items]
Total assets	1,018.7	972.8
Terminaling and Export \| Operating Segments
Segment Reporting Information [Line Items]
Total assets	$ 322.8	$ 330.8