Northern Tier Energy 10-K 27 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 26, 2015	Jun. 30, 2014
Document Information [Line Items]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	NTI
Entity Registrant Name	Northern Tier Energy LP
Entity Central Index Key	1533454
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		92,832,210
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$1,515,661,445

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
CURRENT ASSETS
Cash and cash equivalents	$87.90	$85.80
Accounts receivable	236	242
Inventories	252.1	173.5
Other current assets	15.2	23.7
Total current assets	591.2	525
NON-CURRENT ASSETS
Equity method investment	80.7	86.2
Property, plant and equipment, net	445.8	446.2
Intangible assets	33.8	33.8
Other assets	28.9	26.6
Total Assets	1,180.40	1,117.80
CURRENT LIABILITIES
Accounts payable	334.3	367
Accrued liabilities	52.6	48.5
Total current liabilities	386.9	415.5
NON-CURRENT LIABILITIES
Long-term debt	354.2	275
Lease financing obligation	8.6	8.4
Other liabilities	27	17.8
Total liabilities	776.7	716.7
Commitments and contingencies	0	0
EQUITY
Accumulated other comprehensive loss	-3.2	-2
Partners' capital (92,712,744 and 92,100,363 units issued and outstanding at December 31, 2014 and 2013, respectively)	406.9	403.1
Total equity	403.7	401.1
Total Liabilities and Equity	$1,180.40	$1,117.80

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical)	Dec. 31, 2014	Dec. 31, 2013	Jul. 31, 2012
Statement of Financial Position [Abstract]
Partners' capital, units issued	92,712,744	92,100,363
Partners' capital, units outstanding	92,712,744	92,100,363	91,915,000

Consolidated_Statements_of_Ope

Consolidated Statements of Operations and Comprehensive Income (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Income Statement [Abstract]
Revenues	$5,556		$4,979.20		$4,653.90
COSTS, EXPENSES AND OTHER
Cost of sales	4,835.90		4,284.20		3,586.60
Direct operating expenses	288.8		262.4		254.1
Turnaround and related expenses	14.9		73.3		26.1
Depreciation and amortization	41.9		38.1		33.2
Selling, general and administrative	87.8		85.8		88.3
Reorganization and related costs	12.9				1.4
Contingent consideration loss	0		0		104.3
Income from equity method investment	-2.2		-10		-12.3
Other (income) loss, net	0.7		-3.8		2.9
Operating Income	275.3		246.1		569.3
Gains (losses) from derivative activities	0		16.1		-269.7
Interest expense, net	-26.6		-26.9		-42.2
Loss on early extinguishment of debt	0		0		-50
INCOME BEFORE INCOME TAXES	248.7		235.3		207.4
Income tax provision	-7.1		-4.2		-9.8
NET INCOME	241.6	[1]	231.1	[1]	197.6
Other comprehensive (loss) income, net of tax	-1.2		0.5		-2.1
COMPREHENSIVE INCOME	240.4		231.6		195.5
EARNINGS PER UNIT INFORMATION:
NET INCOME	241.6	[1]	231.1	[1]	197.6
Net Income prior to initial public offering on July 31, 2012					-70.7
Net Income available to common unitholders	241.6		231.1		126.9
Weighted average number of units outstanding, Basic	92,222,793		91,915,335		91,915,000
Weighted average number of units outstanding, Diluted	92,260,045		91,915,335		91,915,000
Earnings per unit, Basic (in dollars per share)	$2.61		$2.51		$1.38
Earnings per unit, Diluted (in dollars per share)	$2.61		$2.51		$1.38
Excise taxes included in revenue and cost of sales	$396.40		$316.40		$300.10
[1]	(a) for 2012 calculations, net income available to common unitholders excludes earnings attributable to the period prior to our IPO date of July 31, 2012

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$241.60	[1]	$231.10	[1]	$197.60
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	41.9		38.1		33.2
Non-cash interest expense	2.8		2.4		7.5
Equity-based compensation expense	14		7.1		0.9
Loss on extinguishment of debt	0		0		50
Deferred income taxes	2.6		0.9		9.8
Contingent consideration loss	0		0		104.3
Loss (gain) from the change in fair value of outstanding derivatives	2.8		-41.6		-68
Loss from lower of cost or market inventory adjustment	73.6		0		0
Changes in assets and liabilities, net:
Accounts receivable	6		-112.7		-47.7
Inventories	-152.3		-11.1		-8.3
Other current assets	9.8		8.3		5.6
Accounts payable and accrued expenses	-28.5		110.3		29.9
Other, net	5.3		-3		-6.3
Net cash provided by operating activities	219.6		229.8		308.5
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	-44.8		-96.6		-30.9
Return of capital from investments	5.3		1.1		2.2
Net cash used in investing activities	-39.5		-95.5		-28.7
CASH FLOWS FROM FINANCING ACTIVITIES
Borrowings from senior secured notes	79.2		0		275
Repayments of senior secured notes	0		0		-290
Premiums paid to extinguish debt	0		0		-39.5
Borrowings from revolving credit arrangement	30		50		0
Repayments of revolving credit arrangement	-30		-50		0
Proceeds from IPO, net of direct costs of issuance	0		0		230.4
Financing costs	-5.4		0		-6.1
Equity distributions	-251.8		-321.4		-300.2
Net cash used in financing activities	-178		-321.4		-130.4
CASH AND CASH EQUIVALENTS
Change in cash and cash equivalents	2.1		-187.1		149.4
Cash and cash equivalents at beginning of period	85.8		272.9		123.5
Cash and cash equivalents at end of period	$87.90		$85.80		$272.90
[1]	(a) for 2012 calculations, net income available to common unitholders excludes earnings attributable to the period prior to our IPO date of July 31, 2012

Consolidated_Statements_of_Par

Consolidated Statements of Partners' Capital and Member's Interest (USD $)	Total		Member's Interest	Common Units	Accumulated Other Comprehensive Income (loss)
In Millions, except Share data
Balance at Dec. 31, 2011	$312.20		$312.60	$0	($0.40)
Balance (in shares) at Dec. 31, 2011				0
Net income	70.7		70.7
Capital distributions	-164.1		-164.1
Capital contribution from parent	45		45
Equity-based compensation, net of forfeitures	1		1
Balance at Jul. 31, 2012	264.8		265.2	0	-0.4
Balance (in shares) at Jul. 31, 2012	91,915,000			0
Balance at Aug. 01, 2012
Net income	126.9		0	126.9
Exchange with NTH of all partnership units in NTE LP for 100% membership interest in NTE LLC (in shares)				91,915,000
Exchange with NTH of all partnership units in NTE LP for 100% membership interest in NTE LLC	0		-265.2	265.2
Proceeds from IPO, net of direct costs of issuance	230.4			230.4
Capital distributions	-136.1			-136.1
Other comprehensive gain/(loss)	-2.1				-2.1
Equity-based compensation, net of forfeitures (in shares)				6,112
Equity-based compensation, net of forfeitures	-0.1			-0.1
Balance at Dec. 31, 2012	483.8		0	486.3	-2.5
Balance (in shares) at Dec. 31, 2012				91,921,112
Net income	231.1	[1]		231.1
Capital distributions	-321.4			-321.4
Other comprehensive gain/(loss)	0.5				0.5
Equity-based compensation, net of forfeitures (in shares)				179,251
Equity-based compensation, net of forfeitures	7.1			7.1
Balance at Dec. 31, 2013	401.1		0	403.1	-2
Balance (in shares) at Dec. 31, 2013	92,100,363			92,100,363
Net income	241.6	[1]		241.6
Capital distributions	-251.8			-251.8
Other comprehensive gain/(loss)	-1.2				-1.2
Equity-based compensation, net of forfeitures (in shares)				612,381
Equity-based compensation, net of forfeitures	14			14
Balance at Dec. 31, 2014	$403.70		$0	$406.90	($3.20)
Balance (in shares) at Dec. 31, 2014	92,712,744			92,712,744
[1]	(a) for 2012 calculations, net income available to common unitholders excludes earnings attributable to the period prior to our IPO date of July 31, 2012

Consolidated_Statements_of_Par1

Consolidated Statements of Partners' Capital and Member's Interest (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Stockholders' Equity [Abstract]
Membership Interest			100.00%
Distributions per common unit (in dollars per share)	$2.71	$3.49	$1.48

Description_of_the_Business_an

Description of the Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business and Basis of Presentation	DESCRIPTION OF THE BUSINESS AND BASIS OF PRESENTATION
	Description of the Business
	Northern Tier Energy LP (“NTE LP” or the “Company”) is an independent downstream energy company with refining, retail and pipeline operations that serve the Petroleum Administration for Defense District II (“PADD II”) region of the United States. NTE LP holds 100% of the membership interest in Northern Tier Energy LLC (“NTE LLC”) and was organized in such a way as to be treated as a master limited partnership (“MLP”) for tax purposes. NTE LLC was a wholly-owned subsidiary of Northern Tier Holdings LLC (“NT Holdings”) until July 31, 2012. On July 31, 2012, NT Holdings contributed all of its membership interests in NTE LLC to NTE LP in connection with the closing of the underwritten initial public offering of NTE LP (the “IPO,” see Note 3). NT Holdings is a wholly-owned subsidiary of Northern Tier Investors LLC (“NT Investors”). NT Investors, NT Holdings and NTE LLC were formed by ACON Refining Partners L.L.C., TPG Refining L.P. and certain members of management (collectively, the “Investors”) during 2010. The St. Paul Park Refinery and Retail Marketing Business were formerly owned and operated by subsidiaries of Marathon Oil Corporation (“Marathon Oil”). These subsidiaries, Marathon Petroleum Company, LP (“MPC LP”), Speedway LLC (“Speedway”) and MPL Investments LLC, are together referred to as “MPC” or “Marathon” and are now subsidiaries of Marathon Petroleum Corporation (“Marathon Petroleum”). Marathon Petroleum was a wholly-owned subsidiary of Marathon Oil until June 30, 2011. Effective December 1, 2010, NTE LLC acquired the business from Marathon for approximately $608 million (the “Marathon Acquisition,” see Note 5).
	NTE LP includes the operations of NTE LLC, St. Paul Park Refining Co. LLC (“SPPR”), Northern Tier Retail Holdings LLC (“NTRH”) and Northern Tier Oil Transport LLC (“NTOT”). NTRH is the parent company of Northern Tier Retail LLC (“NTR”) and Northern Tier Bakery LLC (“NTB”). NTR is the parent company of SuperAmerica Franchising LLC (“SAF”). In connection with the IPO (see Note 3), NTE LLC contributed all of its membership interests in NTR, NTB and SAF to NTRH in exchange for all of the membership interests in NTRH. Effective August 1, 2012, NTRH elected to be treated as a corporation for income tax purposes in order to preserve the MLP tax status of NTE LP. SPPR has a 17% interest in MPL Investments and a 17% interest in Minnesota Pipe Line Company, LLC (“MPL”). MPL Investments owns 100% of the preferred interest in MPL which owns and operates a 455,000 barrel per day (“bpd”) crude oil pipeline in Minnesota (see Note 2). NTOT is a crude oil trucking business in North Dakota that collects crude oil directly from wellheads in the Bakken Shale and transports it to regional pipeline and rail facilities.
	On November 5, 2013, NT Holdings formed a new subsidiary, NT InterHoldCo LLC, and contributed all of its interest in NTE LP and Northern Tier Energy GP LLC, the non-economic general partner of NTE LP, to NT InterHoldCo LLC. Subsequent to the contribution, NT Holdings entered into a definitive agreement to sell all of their interests in NT InterHoldCo LLC to Western Refining, Inc. (“Western Refining”) for total consideration of $775 million plus the distribution on the common units acquired with respect to the quarter ended September 30, 2013. At the time of this transaction, Western Refining indirectly owned 100% of Northern Tier Energy GP LLC, the general partner of NTE LP, and 35,622,500 common units, or 38.7%, of NTE LP. The balance of the limited partner units remain publicly traded. NTE LP received no proceeds from this transaction.
	As of December 31, 2014, SPPR, which is located in St. Paul Park, Minnesota, has total crude oil throughput capacity of 97,800 barrels per stream day. Refining operations include crude fractionation, catalytic cracking, hydrotreating, reforming, alkylation, sulfur recovery and a hydrogen plant. The refinery processes predominately North Dakota and Canadian crude oils into products such as gasoline, diesel, jet fuel, kerosene, asphalt, propane, propylene and sulfur. The refined products are sold to markets primarily located in the Upper Great Plains of the United States.
	As of December 31, 2014, NTR operates 165 convenience stores under the SuperAmerica brand and SAF supports 89 franchised stores which also utilize the SuperAmerica brand. These 254 SuperAmerica stores are primarily located in Minnesota and Wisconsin and sell gasoline, merchandise, and in some locations, diesel fuel. There is a wide range of merchandise sold at the stores including prepared foods, beverages and non-food items. The merchandise sold includes a significant number of proprietary items.
	NTB prepares and distributes food products under the SuperMom’s Bakery brand primarily to SuperAmerica branded retail outlets.
	Basis of Presentation
	The accompanying consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”).

Summary_of_Principal_Accountin

Summary of Principal Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Principal Accounting Policies	SUMMARY OF PRINCIPAL ACCOUNTING POLICIES
	Principles of Consolidation
	NTE LP is a Delaware limited partnership that was established as Northern Tier Energy, Inc. on October 24, 2011 and was subsequently converted into NTE LP as of June 4, 2012. On July 31, 2012, NTE LP closed its IPO whereby it sold 18,687,500 limited partnership units to the public. In connection with the closing of the IPO, NT Holdings contributed all of its membership interests in NTE LLC to NTE LP in exchange for 54,844,500 common units and 18,383,000 PIK units, which were subsequently converted into common units, of NTE LP (see Note 3). Upon the closing of the IPO, the consolidated historical financial statements of NTE LLC became the historical financial statements of NTE LP. NTE LP consolidates all accounts of NTE LLC and its direct subsidiaries.
	The Company’s common equity interest in MPL is accounted for using the equity method of accounting in accordance with the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”) Topic 323. Equity income from MPL represents the Company’s proportionate share of net income available to common equity owners generated by MPL.
	The equity method investment is assessed for impairment whenever changes in facts or circumstances indicate a loss in value has occurred. When the loss is deemed to be other than temporary, the carrying value of the equity method investment is written down to fair value, and the amount of the write-down is included in net income. See Note 8 for further information on the Company’s equity method investment.
	MPL Investments owns all of the preferred membership units of MPL. This investment in MPL Investments, which provides the Company no significant influence over MPL Investments, is accounted for as a cost method investment. The investment in MPL Investments is carried at a value of $6.8 million as of both December 31, 2014 and 2013 and is included in other noncurrent assets within the consolidated balance sheets.
	Use of Estimates
	The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the respective reporting periods. Actual results could differ from those estimates.
	Operating Segments
	The Company has two reportable operating segments; Refining and Retail (see Note 21 for further information on the Company’s operating segments). The Refining and Retail operating segments consist of the following:
	•	Refining – operates the St. Paul Park, Minnesota refinery, terminal and related assets, NTOT and includes the Company’s interest in MPL and MPL Investments, and
	•	Retail – operates 165 convenience stores primarily in Minnesota and Wisconsin. The retail segment also includes the operations of SAF and NTB.
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with maturities of three months or less from the date of purchase to be cash equivalents.
	Receivables and Allowance for Doubtful Accounts
	Receivables of the Company primarily consist of customer accounts receivable. The accounts receivable are due from a diverse base including companies in the petroleum industry, airlines and governmental entities. The allowance for doubtful accounts is reviewed regularly for collectability. All customer receivables are recorded at the invoiced amounts and generally do not bear interest. When it becomes probable the receivable will not be collected, the balances for customer receivables are charged directly to bad debt expense. The allowance for doubtful accounts was $0.2 million as of both December 31, 2014 and 2013.
	Inventories
	Crude oil, refined product and other feedstock and blendstock inventories are carried at the lower of cost or market ("LCM"). Cost is determined principally under the last-in, first-out (“LIFO”) valuation method to reflect a better matching of costs and revenues for refining inventories. Costs include both direct and indirect expenditures incurred in bringing an item or product to its existing condition and location. Ending inventory costs in excess of market value are written down to net realizable market values and charged to cost of sales in the period recorded. In subsequent periods, a new LCM determination is made based upon current circumstances. The Company has LIFO pools for crude oil and other feedstocks and for refined products in its Refining segment and a LIFO pool for refined products inventory held by the retail stores in its Retail segment. Retail merchandise inventory is valued using the average cost method.
	Property, Plant and Equipment
	Property, plant and equipment is recorded at cost and depreciated on a straight-line basis over the estimated useful lives of the assets. Such assets or asset groups are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the expected undiscounted future cash flows from the use of the asset and its eventual disposition is less than the carrying amount of the asset, an impairment loss is recognized based on the fair value of the asset.
	When property, plant and equipment depreciated on an individual basis is sold or otherwise disposed of, any gains or losses are reported in the consolidated statements of operations. Gains on the disposal of property, plant and equipment are recognized when earned, which is generally at the time of sale. If a loss on disposal is expected, such losses are generally recognized when the assets are classified as held for sale.
	Expenditures for routine maintenance and repair costs are expensed when incurred. Refinery process units require periodic major maintenance and repairs that are commonly referred to as “turnarounds.” The required frequency of the maintenance varies by unit, but generally is every two to six years depending on the processing unit involved. Turnaround costs are expensed as incurred.
	Intangible Assets
	Intangible assets primarily include a retail marketing trade name and franchise agreements. These assets have an indefinite life and therefore are not amortized, but rather are tested for impairment annually or when events or changes in circumstances indicate that the fair value of the intangible asset has been reduced below carrying value. If the estimated fair value is less than the carrying amount of the asset, an impairment loss is recognized based on the estimated fair value of the asset. Significant assumptions in determining the estimated fair value of the indefinite lived intangibles include projected store growth, estimated market royalty rates, market growth rates and the estimated discount rate.
	Renewable Identification Numbers
	The Company is subject to obligations to generate or purchase Renewable Identification Numbers ("RINs") required to comply with the Renewable Fuels Standard. The Company's overall RINs obligation is based on a percentage of domestic shipments of on-road fuels as established by the Environmental Protection Agency ("EPA"). To the degree the Company is unable to blend the required amount of biofuels to satisfy our RINs obligation, RINs must be purchased on the open market to avoid penalties and fines. The Company records its RINs obligation on a net basis in accrued liabilities when its RINs liability is greater than the amount of RINs earned and purchased in a given period and in other current assets when the amount of RINs earned and purchased is greater than the RINs liability.
	Financing Costs
	Financing origination fees on the Company's senior secured notes, ABL Facility and sales-leaseback transaction are deferred and classified within other assets on the consolidated balance sheets. Amortization is provided on a straight-line basis over the term of the agreement, which approximates the effective interest method.
	Revenue Recognition
	Revenues are recognized when products are shipped or services are provided to customers, title is transferred, the sales price is fixed or determinable and collectability is reasonably assured. Revenues are recorded net of discounts granted to customers. Shipping and other transportation costs billed to customers are presented on a gross basis in revenues and cost of sales.
	Nonmonetary product exchanges and certain buy/sell crude oil transactions which are entered into in contemplation one with another are included on a net cost basis in cost of sales. The Company also enters into agreements to purchase and sell crude oil to third parties and certain of these activities are recorded on a gross basis.
	Prior to the fourth quarter of 2014, the Company maintained a crude oil supply and logistics agreement with JPM CCC pursuant to which JPM CCC assisted the Company in the purchase of substantially all of its crude oil needs for the refinery. As discussed in Note 7, JPM CCC and the Company mutually agreed to terminate this agreement. In the fourth quarter of 2014, subsequent to the termination of this agreement, the Company has significantly increased its crude procurement activities and related exchange and buy/sell activity to manage the volumes, grade, timing, and locations of such crude. Such activities are similar to the buy/sell crude oil transactions noted above and are recorded net in cost of sales.
	Product Exchanges
	The Company enters into exchange contracts whereby it agrees to deliver a particular quantity and quality of crude oil or refined products at a specified location and date to a particular counterparty and to receive from the same counterparty a particular quantity and quality of crude oil or refined products at a specified location on the same or another specified date. The exchange receipts and deliveries are nonmonetary transactions, with the exception of associated grade or location differentials that are settled in cash. These transactions are recorded net in cost of sales because they involve the exchange of inventories held in the ordinary course of business to facilitate sales to customers or delivery of feedstocks to our refinery. The exchange transactions are recognized at the carrying amount of the inventory transferred plus or minus any cash settlement due to grade or location differentials.
	Cost of Sales
	Cost of sales in the consolidated statements of operations and comprehensive income excludes depreciation and amortization of refinery assets and the direct labor and overhead costs related to the operation of the refinery. These costs are included in the consolidated statements of operations and comprehensive income in the depreciation and amortization and direct operating expenses line items, respectively.
	Excise Taxes
	The Company is required by various governmental authorities, including federal and state, to collect and remit taxes on certain products. Such taxes are presented on a gross basis in revenue and cost of sales in the consolidated statements of operations. These taxes totaled $396.4 million, $316.4 million and $300.1 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	Derivative Financial Instruments
	The Company is exposed to earnings and cash flow volatility based on the timing and change in refined product prices and crude oil prices. To manage these risks, the Company may use derivative instruments associated with the purchase or sale of crude oil and refined products. Crack spread futures and swap contracts may be used to hedge the volatility of refining margins. The Company may also use futures contracts to manage price risks associated with inventory quantities above or below target levels. All derivative instruments are recorded in the consolidated balance sheet at fair value and are classified depending on the maturity date of the underlying contracts. Changes in the fair value of its contracts are accounted for by marking them to market and recognizing any resulting gains or losses in the statements of operations. Gains and losses from derivative activity specific to the mitigation on inventory quantities are included within cost of sales. Gains and losses from derivative activity specific to the risk mitigation on the crack spread futures and swap derivatives are included within gains (losses) on derivative activities. Derivative gains and losses are reported as operating activities within the consolidated statements of cash flows.
	We enter into crude oil forward contracts to facilitate the supply of crude oil to the refinery. These contracts may qualify for the normal purchases and normal sales exception because we physically receive and deliver the crude oil under the contracts and when we enter into these contracts, the quantities are expected to be used or sold over a reasonable period of time in the normal course of business. These transactions are reflected in the period that delivery of the crude oil takes place.
	Advertising
	The Company expenses the costs of advertising as incurred. Advertising expense was $2.3 million, $2.0 million and $1.5 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	Asset Retirement Obligations
	The fair value of asset retirement obligations is recognized in the period in which the obligations are incurred if a reasonable estimate of fair value can be made. Conditional asset retirement obligations for removal and disposal of fire-retardant material from certain refining assets have been recognized. The amounts recorded for such obligations are based on the most probable current cost projections. Asset retirement obligations have not been recognized for the removal of materials and equipment from or the closure of certain refinery, pipeline, terminal and retail marketing assets because the fair value cannot be reasonably estimated since the settlement dates of the obligations are indeterminable. Current inflation rates and credit-adjusted-risk-free interest rates are used to estimate the fair value of asset retirement obligations. Depreciation of capitalized asset retirement costs and accretion of asset retirement obligations are recorded over time. Depreciation is determined on a straight-line basis, while accretion escalates over the lives of the assets. See further information on our asset retirement obligations in Note 15.
	Environmental Costs
	Environmental expenditures are capitalized if the costs mitigate or prevent future contamination or if the costs improve environmental safety or efficiency of the existing assets. The Company provides for remediation costs and penalties when the responsibility to remediate is probable and the amount of associated costs can be reasonably estimated. The timing of remediation accruals coincides with completion of feasibility studies, investigations or the commitment to a formal plan of action. Environmental liabilities are difficult to assess and estimate due to uncertainties related to the magnitude of possible remediation and the timing of such remediation. Such estimates are subject to change due to many factors, including the identification of new sites requiring remediation, changes in environmental laws and regulations and their interpretation, additional information related to the extent and nature of remediation efforts and potential improvements in remediation technologies. Remediation liabilities are accrued based on estimates of known environmental exposure and are discounted when the estimated amounts are reasonably fixed and determinable. If recoveries of remediation costs from third parties are probable, a receivable is recorded and is discounted to net present value when the estimated amount is reasonably fixed and determinable.
	Defined Benefit Plans
	The Company has a cash balance plan and a retiree medical plan that are considered defined benefit plans. Expenses and liabilities related to defined benefit plans are determined on an actuarial basis and are affected by the market value of plan assets, estimates of the expected return on plan assets, and assumed discount rates and demographic data.
	Cash balance and retiree medical plan expenses and liabilities are determined based on actuarial valuations. Inherent in these valuations are key assumptions including discount rates, future compensation increases, expected return on plan assets, health care cost trends, and demographic data. Changes in our actuarial assumptions are primarily influenced by factors outside of our control and could have a significant effect on our pension and retiree medical liabilities and costs. See further information on our plans in Note 17.
	Equity-Based Compensation
	The Company recognizes compensation expense for equity-based awards issued over the requisite service period. Equity-based compensation costs are measured at the date of grant, based on the fair value of the award. In 2014, the Company began awarding phantom common units which, at the discretion of the board of directors of our general partner, may be settled in either cash or the Company's common units. The first tranche of phantom unit vesting occurred in January 2015 and was settled in common units. We anticipate that the remaining unvested phantom units will ultimately be satisfied with common units and have therefore classified the accrual of the service cost as equity. However, if our general partner's board elects to settle the phantom units with cash, it could cause us to remeasure the fair value of those awards resulting in an adjustment to earnings for the cumulative difference between the fair value at the date of grant and date of the remeasurement.
	Income Taxes
	Effective August 1, 2012, NTRH elected to be treated as a corporation for income tax purposes in order to preserve the MLP tax status of NTE LP. As such, the Company has recorded deferred tax assets and deferred tax liabilities related to NTRH as of the election date. Additionally, the Company recorded current period income taxes for all periods subsequent to August 1, 2012 (see Note 6) at the NTRH level. Prior to August 1, 2012, all of the Company’s income was derived from subsidiaries which were limited liability companies and were therefore pass-through entities for federal income tax purposes. As a result, the Company did not incur federal income taxes prior to this date. The Company’s policy is to recognize interest related to any underpayment of taxes as interest expense and any penalties as administrative expenses.
	Comprehensive Income
	The Company has unrecognized prior service cost related to its defined benefit cash balance plan as of December 31, 2014, 2013 and 2012 and unrecognized actuarial losses and prior service cost related to its retiree medical plan as of December 31, 2014 and 2013 (see Note 17). The accumulated unrecognized costs related to these plans amount to $3.2 million and $2.0 million as of December 31, 2014 and 2013, respectively. These gains/(losses) of $(1.2) million, $0.5 million and $(2.1) million were recognized directly to equity as an element of other comprehensive income (loss) in the years ended December 31, 2014, 2013 and 2012, respectively.
	Concentrations of Risk
	The Company is exposed to credit risk in the event of nonpayment by customers. The creditworthiness of customers is subject to continuing review. No single non-related party customer accounts for more than 10% of annual revenues.
	Crude oil is the principal raw material for the Company and the majority of the crude oil processed is delivered to the refinery through a pipeline that is owned by MPL, a related party. A prolonged disruption of that pipeline’s operations would materially impact the Company’s ability to economically obtain raw materials.
	The Company is exposed to concentrated geographical risk as most of its operations are conducted in the Upper Great Plains of the United States.
	Reclassifications
	Certain reclassifications have been made to the prior-year financial information in order to conform to the Company’s current presentation, which is intended to conform with Western Refining's presentation. The following reclassifications have been made:
	Derivatives
	Related to our derivative activities, a $7.4 million net gain and a $1.7 million net loss from derivative activity not related to our crack spread hedges have been reclassified from gains (losses) from derivative activities to cost of sales for the years ended December 31, 2013 and 2012, respectively, within the consolidated statements of operations and comprehensive income.
Income from equity method investment
Income from our equity method investment in MPL has been reclassified from other (income) loss, net to a separate line titled income from equity method investment. The amount of this reclassification was income of $10.0 million and $12.3 million for the years ended December 31, 2013 and 2012, respectively.
Recent Accounting Pronouncements
In April 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-08, which updated the guidance in ASC Topic 205, “Presentation of Financial Statements”, and ASC Topic 360, “Property, Plant and Equipment.” This ASU raises the threshold for a disposal to qualify as discontinued operations and requires new disclosures for individual material disposal transactions that do not meet the definition of a discontinued operation.  Under the new standard, companies report discontinued operations when they have a disposal that represents a strategic shift that has or will have a major impact on operations or financial results.  This update will be applied prospectively and is effective for annual periods, and interim periods within those years, beginning after December 15, 2014.  Early adoption is permitted provided the disposal was not previously disclosed.  The adoption of this guidance is not expected to have a material impact on our results of operations, cash flows or financial position.
In May 2014, the FASB issued ASU No. 2014-09 “Revenue from Contracts with Customers,” which provides guidance for revenue recognition. The standard’s core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This guidance will be effective for our financial statements in the annual period beginning after December 15, 2016. We are evaluating the effect of adopting this new accounting guidance we do not expect adoption will have a material impact on our results of operations, cash flows or financial position.
In August 2014, the FASB issued ASU No. 2014-15 “Presentation of Financial Statements - Going Concern,” which sets forth new provisions that require management of an entity to evaluate whether there is substantial doubt about the entity's ability to continue as a going concern and to provide related footnote disclosures. This guidance will become effective for annual periods beginning after December 15, 2016, and for annual periods and interim periods thereafter with early application permitted. The changed requirements are intended to reduce diversity in the timing and content of footnote disclosures. We do not expect the adoption of these new provisions to materially affect our financial position, results of operations or cash flows.

Initial_Public_Offering_of_Nor

Initial Public Offering of Northern Tier Energy LP	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Initial Public Offering of Northern Tier Energy LP	INITIAL PUBLIC OFFERING OF NORTHERN TIER ENERGY LP
	On July 25, 2012, NTE LP priced 16,250,000 common units in its IPO at a price of $14.00 per unit, and on July 26, 2012, NTE LP common units began trading on the New York Stock Exchange (ticker symbol: NTI). NTE LP closed its IPO of 18,687,500 common units, which included 2,437,500 common units issued pursuant to the underwriters’ exercise of their option to purchase additional common units, on July 31, 2012.
	The net proceeds from the IPO of approximately $245 million, after deducting the underwriting discount, along with approximately $56 million of cash on hand were used to: (i) distribute approximately $124 million to NT Holdings, of which approximately $92 million was used to redeem Marathon’s existing preferred interest in NT Holdings and $32 million was distributed to ACON Refining Partners L.L.C., TPG Refining L.P. and entities in which certain members of the Company’s management team hold an ownership interest, (ii) pay $92 million to J. Aron & Company, an affiliate of Goldman, Sachs & Co., related to deferred payment obligations from the early extinguishment of derivatives (see Note 11), (iii) pay $40 million to Marathon, which represents the cash component of a settlement agreement NTE LLC entered into with Marathon in satisfaction of a contingent consideration arrangement that was part of the Marathon Acquisition (see Note 5), (iv) redeem $29 million of NTE LLC senior secured notes at a redemption price of 103% of the principal amount thereof, plus accrued interest, for an estimated $31 million, and (v) pay other offering costs of approximately $15 million.
	In connection with the closing of the IPO the following transactions and events occurred in the third quarter of 2012:
	•	The settlement agreement with Marathon with respect to the contingent consideration arrangements that were entered into in connection with the Marathon Acquisition became effective (see Note 5);
	•	The Company’s management services agreement with ACON Refining Partners L.L.C and TPG Refining L.P. (see Note 4) was terminated;
	•	NT Holdings contributed all of its membership interests in NTE LLC to NTE LP in exchange for 54,844,500 common units and 18,383,000 PIK units;
	•	NTE LP issued 18,687,500 common units to the public, representing a 20.3% limited partner interest; and
	•	NTRH elected to be treated as a corporation for federal income tax purposes, subjecting it to corporate-level tax.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS
	The original investors in NTE LLC, which included ACON Refining Partners L.L.C. and TPG Refining L.P., were related parties of the Company from inception through November 12, 2013, the date they sold their remaining indirect interest in the Company to a subsidiary of Western Refining (see Note 1). Upon execution of that transaction, Western Refining became a related party to the Company. For the year ended December 31, 2014, the Company purchased $6.3 million of crude oil from a subsidiary of Western Refining. During the year ended December 31, 2014, the Company sold asphalt and RINs at market price totaling $19.0 million to Western Refining (see Note 2). Additionally, for the year ended December 31, 2014, the Company realized $0.1 million in lease revenue from the sublease of railcars to a subsidiary of Western Refining.
	On October 30, 2014, the Company entered into a shared services agreement with Western Refining whereby the Company receives administrative support services. The shared services agreement is effective as of September 1, 2014, and was approved by the Conflicts Committee of the Company's Board of Directors. These services include assistance with treasury, risk management and commercial operations, environmental compliance, information technology support, legal and others. For the year ended December 31, 2014, the Company recognized $1.1 million in expense for these services, which are included in selling, general and administrative expenses. As of December 31, 2014, Western Refining owed the Company $5.1 million. There were no related party transactions with Western Refining during the year ended December 31, 2013.
	MPL is also a related party of the Company, however the Company had a crude oil supply and logistics agreement with a third party until September 30, 2014 and had no direct supply transactions with MPL prior to this date. Beginning on September 30, 2014, the Company began paying MPL for transportation services at published tariff rates. During the year ended December 31, 2014, we incurred $12.6 million in crude transportation costs with MPL. As of December 31, 2014, the Company owed MPL $2.1 million.
	Upon completion of the Marathon Acquisition, the Company entered into a management services agreement with the Investors pursuant to which they provided the Company with ongoing management, advisory and consulting services. This management services agreement was terminated in conjunction with the IPO of NTE LP as of July 31, 2012. While this agreement was in effect, the Investors also received quarterly management fees equal to 1% of the Company’s “Adjusted EBITDA” (as defined in the agreement) for the previous quarter (subject to a minimum annual fee of $2 million), as well as reimbursements for out-of pocket expenses incurred by them in connection with providing such management services. The Company recognized management fees relating to these services of $3.1 million for the year ended December 31, 2012. As a result of the IPO, the Company was required to pay the Investors a specified success fee of $7.5 million that is a part of the IPO offering expenses discussed in Note 3.

Marathon_Acquisition

Marathon Acquisition	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Marathon Acquisition	MARATHON ACQUISITION
	As previously described in Note 1, effective December 1, 2010, the Company acquired the business from MPC for $608 million. Included in the purchase agreement were contingent consideration arrangements under which the Company could have received margin support payments of up to $60 million from MPC or could have paid MPC net earn-out payments of up to $125 million over the term of the arrangements, depending on the Company’s Adjusted EBITDA as defined in the arrangements. On May 4, 2012, NTE LLC entered into a settlement agreement with MPC regarding the contingent consideration arrangements. The settlement agreement was contingent upon the consummation of the IPO, which occurred on July 31, 2012 (see Note 3). Upon the consummation of the NTE LP IPO, the Company reversed the amounts recorded for the margin support and earn-out arrangements and recorded a liability of $85 million representing the amount of the settlement agreement. The net impact of these adjustments resulted in a charge of $104.3 million recognized during the year ended December 31, 2012.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES
	On July 31, 2012, NTRH was established as the parent company of NTR and NTB. NTRH elected to be taxed as a corporation for federal and state income tax purposes effective August 1, 2012. Prior to that, no provision for income tax was calculated on earnings of the Company or its subsidiaries as all entities were non-taxable.
			Year Ended December 31,
	(in millions)		2014				2013				2012
	Current tax expense		$	4.5			$	3.3			$	—
	Deferred tax expense		$	2.6			$	0.9			$	9.8
	Income tax provision		$	7.1			$	4.2			$	9.8
	On August 1, 2012, the Company recorded an $8.0 million tax charge to recognize its deferred tax asset and liability positions as of NTRH’s election to be taxed as a corporation. As of NTRH’s election date, the Company recorded a current deferred tax asset of $2.2 million, included in other current assets, and a non-current deferred tax liability of $10.2 million, included in other liabilities.
	The Company’s effective tax rate for the years ended December 31, 2014, 2013 and 2012 was 2.9%, 1.8% and 4.7%, respectively, as compared to the Company's consolidated federal and state expected statutory tax rate of 40.4% for all periods. The Company's effective tax rate was lower than the statutory rate for the years ended December 31, 2014, 2013 and 2012 primarily due to the fact that only the retail operations of the Company are taxable entities. Additionally, the year ended December 31, 2012 was impacted by the opening deferred tax charge of $8.0 million which had the effect of increasing the effective tax rate.
	The following is a reconciliation of income tax expense to income taxes computed by applying the applicable statutory federal income tax rate of 35% to income before income taxes for the applicable periods:
			Year Ended December 31,
	(in millions)		2014				2013				2012
	Federal statutory rate applied to income before taxes		$	87			$	82.4			$	72.6
	Taxes on earnings attributable to flow-through entities		(81.0		)		(78.6		)		(71.6		)
	State and local income taxes, net of federal income tax effects		1				0.9				—
	Initial charge upon NTRH's election to be treated as a corporation		—				—				8
	Work opportunity tax credit		(0.3		)		(0.6		)		—
	Other, net		0.4				0.1				0.8
	Income tax provision		$	7.1			$	4.2			$	9.8
	As a result of the Company’s analysis, management has determined that the Company does not have any material uncertain tax positions. As of December 31, 2012, the Company had tax loss carryforwards of approximately $2.1 million which were fully utilized in 2013. As of December 31, 2014 and 2013, the Company had no deferred tax assets arising from net operating losses. The Company is subject to U.S. federal and state income tax examinations for tax years from its date of inception. The Company classifies interest to be paid on an underpayment of income taxes and any related penalties as income tax expense.
	The net deferred tax assets (liabilities) as of December 31, 2014 and 2013 consisted of the following components:
					December 31,
	(in millions)				2014				2013
	Deferred tax assets:
		Lease financing obligations			2.4				2.6
		Customer loyalty accrual			0.9				0.9
		Other			0.8				1.1
	Total deferred taxes, net				4.1				4.6
	Deferred tax liabilities:
		Accelerated depreciation			$	(5.4	)		$	(3.4	)
		Intangible assets			(11.8		)		(11.7		)
		Other			(0.2		)		(0.2		)
	Deferred tax liabilities				(17.4		)		(15.3		)
					$	(13.3	)		$	(10.7	)
	The net deferred tax assets (liabilities) are included in the December 31, 2014 and 2013 balance sheets as components of other current assets and other liabilities.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventories	INVENTORIES
		December 31,
	(in millions)	2014			2013
	Crude oil and refinery feedstocks	$	137.5		$	29.4
	Refined products	150			106.7
	Merchandise	22.3			22.6
	Supplies and sundry items	15.9			14.8
		325.7			173.5
	Lower of cost or market inventory reserve	(73.6		)	—
	Total	$	252.1		$	173.5
	Inventories accounted for under the LIFO method comprised 88% and 78% of the total inventory value at December 31, 2014 and 2013, respectively.
	Historically, the Company maintained a crude oil supply and logistics agreement with JPM CCC pursuant to which JPM CCC assisted the Company in the purchase of the crude oil for its storage tanks at Cottage Grove, Minnesota, which are approximately two miles from the refinery. Upon delivery of the crude oil to the Company, we paid JPM CCC the price of the crude oil plus certain agreed fees and expenses. JPMorgan Chase & Co. had announced its intention to sell the physical portions of its commodities business (which includes JPM CCC) to Mercuria Energy Group Ltd. during the fourth quarter of 2014. In advance of this sale, JPM CCC and the Company mutually agreed to terminate the Crude Intermediation Agreement. This resulted in our acquisition of approximately 1.2 million barrels of crude oil inventory from JPM CCC as of September 30, 2014. This purchase of crude oil from JPM CCC in September 2014 resulted in an additional layer of inventory subject to the LIFO valuation method.
	In the fourth quarter of 2014, market prices of feedstocks and refined products decreased significantly. Because of this, the Company reduced the carrying value of its inventory by $73.6 million in order to state the value at market prices, which were lower than our LIFO cost at December 31, 2014.
	During 2013, reductions in quantities of refined products inventory resulted in a liquidation of LIFO inventory quantities acquired at higher costs in prior years. The 2013 LIFO liquidation resulted in an increase in cost of sales of approximately $1.0 million. There were no such LIFO liquidations during 2014 or 2012.

Equity_Method_Investment

Equity Method Investment	12 Months Ended
	Dec. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investment	EQUITY METHOD INVESTMENT
	The Company has a 17% common equity interest in MPL. The carrying value of this equity method investment was $80.7 million and $86.2 million at December 31, 2014 and 2013, respectively.
	Summarized financial information for MPL is as follows:
				Year Ended December 31,
	(in millions)			2014		2013		2012
	Revenues			$	184.7	$	161.9	$	153.6
	Operating costs and expenses			141.3		74.5		52.7
	Income from operations			43.4		68.2		82.1
	Net income			22.8		68.2		82.1
	Net income available to MPL common members			13.1		58.6		72.4
				December 31,
	(in millions)			2014		2013
	Balance sheet data:
		Current assets		$	9.6	$	26.1
		Noncurrent assets		450.7		462.9
			Total assets	$	460.3	$	489
		Current liabilities		$	21.9	$	19.8
		Noncurrent liabilities		—		—
			Total liabilities	$	21.9	$	19.8
		Members capital		$	438.4	$	469.2
	As of December 31, 2014 and 2013, the carrying amount of the equity method investment was $6.2 million and $6.4 million higher than the underlying net assets of the investee, respectively. The Company is amortizing this difference over the remaining life of MPL’s primary asset (the fixed asset life of the pipeline).
	Distributions received from MPL were $7.5 million, $11.1 million and $14.5 million for the years ended December 31, 2014, 2013 and 2012, respectively. Equity income from MPL was $2.2 million, $10.0 million and $12.3 million for the years ended December 31, 2014, 2013 and 2012, respectively.

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT
	Major classes of property, plant and equipment (“PP&E”) consisted of the following:
		Estimated	December 31,
	(in millions)	Useful Lives	2014			2013
	Land		$	9		$	9
	Retail stores and equipment	2 - 22 years	65.7			54.9
	Refinery and equipment	5 - 24 years	444.6			403.5
	Buildings and building improvements	25 years	10.2			8.9
	Software	5 years	18.8			18.6
	Vehicles	5 years	4.7			4.7
	Other equipment	2 - 7 years	9.1			8.5
	Precious metals		10.2			10.2
	Assets under construction		12.6			26.3
			584.9			544.6
	Less: Accumulated depreciation		(139.1		)	(98.4		)
	Property, plant and equipment, net		$	445.8		$	446.2
	PP&E includes gross assets acquired under capital leases of $10.8 million and $8.6 million at December 31, 2014 and 2013, respectively, with related accumulated depreciation of $1.7 million and $1.2 million, respectively. The Company had depreciation expense related to capitalized software of $3.7 million, $3.7 million and $3.2 million for years ended December 31, 2014, 2013 and 2012, respectively.

Intangible_Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	INTANGIBLE ASSETS
	Intangible assets are comprised of franchise rights and trade name amounting to $33.8 million at both December 31, 2014 and 2013. At both December 31, 2014 and 2013, the franchise rights and trade name intangible asset values were $12.4 million and $21.4 million, respectively. These assets have an indefinite life and are not amortized, but rather are tested for impairment annually or when events or changes in circumstances indicate that the fair value of the intangible asset has been reduced below carrying value. Historically, the Company performed its annual indefinite lived intangible testing as of October 31. During 2014, we changed the date of our annual impairment test to June 30. Based on the testing performed as of June 30, 2014, the Company noted no indications of impairment.
	During the Company’s intangible assets impairment test for the year ended December 31, 2013, the Company identified a prior period error in the initial valuation of intangibles at inception on December 1, 2010. The impact of the error, which was immaterial to previously issued financial statements, resulted in an overstatement in the value of intangible assets at inception of $1.6 million. In the fourth quarter of 2013, an out-of-period adjustment was recorded to reduce intangible assets by $1.6 million and to reduce other liabilities by $0.6 million, for the related impact on long-term deferred tax liabilities. The Company recognized a $1.6 million charge, included in reorganization and related costs, and a $0.6 million income tax benefit to correct this immaterial error.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	DERIVATIVES
	The Company is subject to crude oil and refined product market price fluctuations caused by supply conditions, weather, economic conditions and other factors. Historically, the Company entered into crack spread derivative contracts as a strategy to mitigate refining margin risk on a portion of its 2011 through 2013 projected refining production. As of December 31, 2013, all of the Company's crack spread derivative contracts had expired and, as such, at both December 31, 2014 and 2013, the Company had no open crack spread derivative instruments.
	The Company periodically use futures and swaps contracts to manage price risks associated with inventory quantities both above and below target levels. Under the Company's risk mitigation strategy, it may buy or sell an amount equal to a fixed price times a certain number of barrels, and to buy or sell in return an amount equal to a specified variable price times the same amount of barrels. Physical volumes are not exchanged and these contracts are net settled with cash. The contracts are not being accounted for as hedges for financial reporting purposes. The Company recognizes all derivative instruments as either assets or liabilities at fair value on the balance sheet and any related net gain or loss is recorded as a gain or loss in the derivative activity captions in the consolidated statements of operations. Observable quoted prices for similar assets or liabilities in active markets (Level 2 as described in Note 14) are considered to determine the fair values for the purpose of marking to market the derivative instruments at each period end.
	At December 31, 2014 and 2013, the Company had open commodity derivative instruments as follows:
		December 31,
		2014			2013
		(in thousands of barrels or barrels of oil equivalent)
	Open commodity hedging instruments:
	Crude oil and refined product futures and swaps, net short positions	(124	)		—
	Natural gas swaps, net long positions	617			—
	All derivative contracts are marked to market at period end and the resulting gains and losses are recognized in earnings.
	Recognized gains and losses on derivatives were as follows:
			Year Ended December 31,
	(in millions)		2014				2013				2012
	Gain (loss) on the change in fair value of outstanding derivatives		$	(2.8	)		$	41.6			$	68
	Settled derivative gains (losses)		12.4				(18.1		)		(339.4		)
	Total recognized gain (loss)		$	9.6			$	23.5			$	(271.4	)
	Gain (loss) recognized in Cost of sales		$	9.6			$	7.4			$	(1.7	)
	Gain (loss) recognized in Gains (losses) from derivative activities		—				16.1				(269.7		)
	Total recognized net gain (loss) on derivatives		$	9.6			$	23.5			$	(271.4	)
	During the first and second quarter of 2012, the Company entered into arrangements to settle or re-price a portion of its existing derivative instruments ahead of their respective expiration dates. The Company incurred $136.8 million of settlement losses related to these early extinguishments. The cash payments for the early extinguishment of these derivative instruments were deferred at the time of settlement. In August 2012, the Company paid $92 million related to these early settlements with the proceeds from the IPO (see Note 3). The remainder of these losses began to come due beginning in September 2012 and were fully paid by January 2014. The early extinguishments were treated as a current period loss as of the date of extinguishment. Interest accrued on the deferred loss liabilities at a weighted average interest rate of 7.1%. Interest expense related to these liabilities was $0.7 million and $2.5 million for the years ended December 31, 2013 and 2012, respectively. The remaining deferred payment obligations related to these early extinguishment losses of $0.9 million are included in the December 31, 2013 balance sheet within current liabilities. At December 31, 2012, $28.9 million of these deferred payment obligations are included in the balance sheet within current liabilities and $0.9 million in long-term liabilities under the accrued liabilities and other liabilities captions, respectively.
	The following table summarizes the fair value amounts of the Company’s outstanding derivative instruments by location on the balance sheet as of December 31, 2014 and 2013:
					December 31,
	(in millions)		Balance Sheet Classification		2014				2013
	Commodity swaps and futures		Other current assets		$	1.7			$	—
	Commodity swaps and futures		Accrued liabilities		(4.1		)		—
	Commodity swaps and futures		Other liabilities		$	(0.4	)		$	—
	Net asset (liability) position				$	(2.8	)		$	—
	The information below presents the notional volume of outstanding contracts by type of instrument and year of maturity at December 31, 2014:
		Notional Contract Volumes by Year of Maturity
		2014			2015
		(in thousands of barrels or barrels of oil equivalent)
	Open commodity hedging instruments:
	Crude oil and refined product futures and swaps, net short positions	(124	)		—
	Natural gas swaps, net long positions	419			198
	The Company is exposed to credit risk in the event of nonperformance by our counterparties on its risk mitigating arrangements. The counterparties are large financial institutions with credit ratings of at least A- by Standard and Poor’s and Baa1 by Moody’s. In the event of default, the Company would potentially be subject to losses on a derivative instrument’s mark-to-market gains. The Company does not expect nonperformance of the counterparties involved in its risk mitigation arrangements.

Debt

Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt	DEBT
	ABL Facility
	On September 29, 2014, the Company and its subsidiaries entered into an amended and restated asset-based ABL Facility with JPMorgan Chase Bank, N.A., as administrative agent for the lenders and as collateral agent for the other secured parties. The borrowers under the ABL Facility are SPPR, NTB, NTR and SAF, each of which is a wholly owned subsidiary of the Company.
	Lenders under the ABL Facility hold commitments totaling $500 million, all of which mature on September 29, 2019. Borrowings under the ABL Facility can be either base rate loans plus a margin ranging from 0.50% to 1.00% or LIBOR loans plus a margin ranging from 1.50% to 2.00%, in each case subject to adjustment based upon the average historical excess availability. The ABL Facility also provides for a quarterly commitment fee ranging from 0.25% to 0.375% per annum, subject to adjustment based upon the average utilization ratio, and letter of credit fees ranging from 1.50% to 2.00% per annum payable quarterly, subject to adjustment based upon the average historical excess availability. The facility may be used for general corporate purposes, including to fund working capital needs and letter of credit requirements. The Company incurred financing costs associated with the new ABL Facility of $3.0 million which are being amortized to interest expense through the date of maturity.
	The ABL Facility is guaranteed, on a joint and several basis, by the Company and its subsidiaries and will be guaranteed by any newly acquired or formed subsidiaries, subject to certain limited exceptions. The ABL Facility and such guarantees are secured on a first priority basis by substantially all of the Company and such subsidiaries’ cash and cash equivalents, accounts receivable and inventory and on a second priority basis by the Company and such subsidiaries’ fixed assets (other than real property).
	The ABL Facility contains certain covenants, including but not limited to limitations on debt, liens, investments, and dividends and the maintenance of a minimum fixed charge coverage ratio in certain circumstances.
	Borrowing availability under the ABL Facility is tied to a borrowing base dependent upon the amount of eligible accounts receivable and inventory. As of December 31, 2014, the borrowing base under the ABL Facility was $308.3 million and availability under the ABL Facility was $296.2 million (which is net of $12.1 million in outstanding letters of credit). The Company had no borrowings under the ABL Facility at December 31, 2014.
	2020 Secured Notes
	At December 31, 2014 and 2013, NTE LLC had outstanding $354 million and $275 million, respectively, in aggregate principal amount of 7.125% senior secured notes due 2020 (the “2020 Secured Notes”). On September 29, 2014, the Company issued an additional $75.0 million of the 2020 Secured Notes at 105.75% of par for gross proceeds of $79.2 million. This offering was issued under the same indenture and associated terms as the existing 2020 Secured Notes. The issuance premium of $4.2 million and financing costs of $2.5 million associated with this offering will both be amortized as a net reduction to interest expense over the remaining life of the notes.
	The 2020 Secured Notes are guaranteed, jointly and severally, on a senior secured basis by all of the Company’s existing and future 100% direct and indirect subsidiaries on a full and unconditional basis; however, there are certain obligations not guaranteed on a full and unconditional basis as a result of subsidiaries being released as guarantors. A subsidiary guarantee can be released under customary circumstances, including (a) the sale of the subsidiary, (b) the subsidiary being declared “unrestricted,” (c) the legal or covenant defeasance or satisfaction and discharge of the indenture, or (d) liquidation or dissolution of the subsidiary. Separate condensed consolidated financial information is not included as the guarantor company, NTE LP, does not have independent assets or operations. The 2020 Secured Notes and the subsidiary note guarantees are secured on a pari passu basis with certain hedging agreements by a first-priority security interest in substantially all present and hereinafter acquired tangible and intangible assets of NTE LLC and each of the subsidiary guarantors and by a second-priority security interest in the inventory, accounts receivable, investment property, general intangibles, deposit accounts and cash and cash equivalents collateralized by the $500 million secured asset-based ABL Facility with a maturity date of September 29, 2019. Additionally, the 2020 Secured Notes are fully and unconditionally guaranteed on a senior unsecured basis by NTE LP. NTE LP's creditors have no recourse to the assets of Western Refining and its subsidiaries. Western Refining's creditors have no recourse to the assets of NTE LP and its subsidiaries. The Company is required to make interest payments on May 15 and November 15 of each year, which commenced on May 15, 2013. There are no scheduled principal payments required prior to the 2020 Secured Notes maturing on November 15, 2020. Effective in October 2013, the original issue of $275 million of the 2020 Secured Notes were registered with the SEC. In January 2015, the follow on offering of $75.0 million was also registered with the SEC.
	At any time prior to the maturity date of the notes, the Company may, at its option, redeem all or any portion of the notes for the outstanding principal amount plus unpaid interest and a make-whole premium as defined in the indenture. If the Company experiences a change in control or makes certain asset dispositions, as defined under the indenture, the Company may be required to repurchase all or part of the notes plus unpaid interest and, in certain cases, pay a redemption premium.
	The 2020 Secured Notes contain certain covenants that, among other things, limit the ability, subject to certain exceptions, of the Company to incur additional debt or issue preferred equity interests, to purchase, redeem or otherwise acquire or retire its equity interests, to make certain investments, loans and advances, to sell, lease or transfer any of its property or assets, to merge, consolidate, lease or sell substantially all of the Company’s assets, to suffer a change of control or to enter into new lines of business.
	Under the terms of the 2020 Secured Notes, the sale of NT InterHoldCo LLC to Western Refining on November 12, 2013 (see Note 1) represented a change in control. This change in control required the Company to extend a thirty day offer to noteholders to repurchase any or all of the notes they held at a price equivalent to 101% of the aggregate principal amount. Upon expiration of the thirty day term, none of the noteholders had accepted the repurchase offer.
	2017 Secured Notes
	The 2017 Secured Notes were guaranteed, jointly and severally, on a senior secured basis by all of the Company’s existing and future direct and indirect subsidiaries; however, not on a full and unconditional basis as a result of subsidiaries being able to be released as guarantors under certain customary circumstances for such arrangements. A subsidiary guarantee can be released under customary circumstances, including (a) the sale of the subsidiary, (b) the subsidiary is declared “unrestricted,” (c) the legal or covenant defeasance or satisfaction and discharge of the indenture, or (d) liquidation or dissolution of the subsidiary. Separate condensed consolidating financial information is not included as the Company does not have independent assets or operations. The Company was required to make interest payments on June 1 and December 1 of each year, which commenced on June 1, 2011. There were no scheduled principal payments required prior to the notes maturing on December 1, 2017. Borrowings bore interest at 10.50%.
	At any time prior to the maturity date of the notes, the Company could, at its option, redeem all or any portion of the notes for the outstanding principal amount plus unpaid interest and a make-whole premium as defined in the indenture.
	During the year ended December 31, 2012, NTE LLC redeemed the 2017 Secured Notes in multiple transactions, $29 million of the principal amount at a redemption price of 103% of the principal thereof out of the proceeds from its IPO (see Note 3), $258 million of the principal amount at a weighted average redemption price of 114.9% of the principal thereof with proceeds from the concurrent issuance of the 2020 Secured Notes and the remaining $3 million of the principal amount at a redemption price of 103% of the principal thereof just subsequent to the second anniversary of the original issuance date. Due to these early redemptions, the Company recognized a non-cash charge of $10.5 million to write off the unamortized deferred financing cost on these bonds and redemption premiums of $39.5 million. The total loss on the early redemptions of $50.0 million is included in the loss on early extinguishment of debt caption on the statement of operations.

Equity

Equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Equity	EQUITY
	Public Offerings
	As discussed in Note 3, concurrent with the closing of the IPO, NT Holdings contributed its membership interests in NTE LLC to NTE LP in exchange for 54,844,500 common units and 18,383,000 PIK common units. Additionally, NTE LP issued 18,687,500 common units to the public for total common units outstanding as of the IPO of 91,915,000, all of which represent limited partnership interests in NTE LP. In November 2012, the PIK common units initially issued to NT Holdings were converted into common units in conjunction with an amendment to the indenture governing the 2017 Secured Notes.
	Additionally, during the year ended December 31, 2013, NT Holdings completed three secondary public offerings of 37,605,000 common units in total. These offerings did not increase the total common units outstanding and the Company received no proceeds. Under the Company’s partnership agreement, the offering costs from subsequent offerings of common units to the public by NT Holdings are incurred by the Company. During the year ended December 31, 2013, the Company incurred $1.5 million of offering costs from these secondary offerings.
	For the year ended December 31, 2013, the Company recognized a charge of $3.1 million for equity offering costs that did not meet the requirements for deferral, related to a secondary public offering of common units held by the owner of the Company's general partner interest at that time, NT Holdings.
	Western Refining Acquisition
	On November 5, 2013, NT Holdings formed a new subsidiary, NT InterHoldCo LLC, and later contributed all of its interest in NTE LP and Northern Tier Energy GP LLC, the non-economic general partner of NTE LP, to NT InterHoldCo LLC. Subsequent to the contribution, on November 12, 2013, NT Holdings entered into a definitive agreement to sell all of its interests in NT InterHoldCo LLC to Western Refining for total consideration of $775 million plus the distribution on the common units acquired with respect to the quarter ended September 30, 2013. As a result of this transaction, Western Refining indirectly owned 100% of Northern Tier Energy GP LLC and 35,622,500 common units, or 38.7%, of NTE LP. The balance of the limited partner units remain publicly traded. NTE LP received no proceeds from this transaction. As of the purchase date, NT InterHoldCo LLC, as the owner of the general partner of NTE LP, has the ability to appoint all of the members of the general partner’s board of directors.
	Distribution Policy
	The Company generally expects to make cash distributions to unitholders of record on the applicable record date within 60 days after the end of each quarter. Distributions will be equal to the amount of available cash generated in such quarter. Available cash for each quarter will generally equal the Company’s cash flow from operations for the quarter excluding working capital changes, less cash required for maintenance capital expenditures, reimbursement of expenses incurred by the general partner of NTE LP and its affiliates, debt service and other contractual obligations and reserves for future operating or capital needs that the board of directors of the general partner of NTE LP deems necessary or appropriate, including reserves for turnaround and related expenses. The amount of quarterly distributions, if any, will vary based on operating cash flow during such quarter. As a result, quarterly distributions, if any, will not be stable and will vary from quarter to quarter as a direct result of variations in, among other factors, (i) operating performance, (ii) cash flows caused by, among other things, fluctuations in the prices of crude oil and other feedstocks and the prices received for finished products, (iii) working capital requirements, (iv) capital expenditures and (v) cash reserves deemed necessary or appropriate by the board of directors of NTE LP’s general partner. Such variations in the amount of the quarterly distributions may be significant. The Company’s general partner has no incentive distribution rights.
	The following table details the quarterly distributions paid to common unitholders since our IPO in July 2012 (in millions, except per unit amounts):
	Date Declared	Date Paid		Common Units and equivalents (in millions)		Distribution per common unit and equivalent			Total Distribution (in millions)
	2012 Distributions:
	November 12, 2012	November 29, 2012		92		$	1.48		$	136.1
	Total distributions paid during 2012					$	1.48		$	136.1
	2013 Distributions:
	11-Feb-13	February 28, 2013		91.9		$	1.27		$	116.7
	13-May-13	May 30, 2013		92.2		$	1.23		113.4
	13-Aug-13	August 29, 2013		92.2		$	0.68		62.7
	11-Nov-13	November 27, 2013		92.2		$	0.31		28.6
	Total distributions paid during 2013					$	3.49		$	321.4
	2014 Distributions:
	February 7, 2014	February 28, 2014		92.7		$	0.41		$	38
	May 6, 2014	May 30, 2014		93		$	0.77		71.6
	August 5, 2014	August 29, 2014		93		$	0.53		49.3
	November 4, 2014	November 25, 2014		93.1		$	1		92.9
	Total distributions paid during 2014					$	2.71		$	251.8
	On February 6, 2015, the Company declared a quarterly distribution of $0.49 per unit to common unitholders of record on February 17, 2015, payable on February 27, 2015. This distribution of approximately $45.6 million in aggregate is based on available cash generated during the three months ended December 31, 2014.
	Other Distributions
	In conjunction with its IPO, NTE LP distributed $124.2 million to NT Holdings. NT Holdings used approximately $92 million of the distribution to redeem MPC’s existing perpetual payment in kind preferred interest in NT Holdings. Prior to the NTE LP IPO, NTE LLC also made distributions of $40.0 million to NT Holdings in 2012.
	Earnings per Unit
	The following tables illustrate the computation of basic and diluted earnings per unit for the years ended December 31, 2014, 2013 and 2012. The Company has outstanding restricted common units under its LTIP program (see Note 16) that participate in non-forfeitable distributions, which requires the Company to calculate earnings per unit under the two-class method. Under this method, distributed earnings and undistributed earnings are allocated between unrestricted common units and restricted common units.
		Year Ended December 31,
	(in millions, except unit and per-unit data)	2014			2013			2012
	Net income available to common unitholders (a)	$	241.6		$	231.1		$	126.9
	Less: income allocated to participating securities	(1.1		)	(0.6		)	—
	Net income attributable to unrestricted common units	$	240.5		$	230.5		$	126.9
	Weighted average unrestricted common units - basic	92,222,793			91,915,335			91,915,000
	Plus: dilutive potential common securities	37,252			—			—
	Weighted average unrestricted common units - diluted	92,260,045			91,915,335			91,915,000
	Basic earnings per unit	$	2.61		$	2.51		$	1.38
	Diluted earnings per unit	$	2.61		$	2.51		$	1.38
	(a) for 2012 calculations, net income available to common unitholders excludes earnings attributable to the period prior to our IPO date of July 31, 2012

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS
	As defined in GAAP, fair value is the price that would be received for the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. GAAP describes three approaches to measuring the fair value of assets and liabilities: the market approach, the income approach and the cost approach, each of which includes multiple valuation techniques. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. The income approach uses valuation techniques to measure fair value by converting future amounts, such as cash flows or earnings, into a single present value amount using current market expectations about those future amounts. The cost approach is based on the amount that would currently be required to replace the service capacity of an asset. This is often referred to as current replacement cost. The cost approach assumes that the fair value would not exceed what it would cost a market participant to acquire or construct a substitute asset of comparable utility, adjusted for obsolescence.
	Accounting guidance does not prescribe which valuation technique should be used when measuring fair value and does not prioritize among the techniques. Accounting guidance establishes a fair value hierarchy that prioritizes the inputs used in applying the various valuation techniques. Inputs broadly refer to the assumptions that market participants use to make pricing decisions, including assumptions about risk. Level 1 inputs are given the highest priority in the fair value hierarchy while Level 3 inputs are given the lowest priority. The three levels of the fair value hierarchy are as follows:
	•	Level 1 – Observable inputs that reflect unadjusted quoted prices for identical assets or liabilities in active markets as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis.
	•	Level 2 – Observable market-based inputs or unobservable inputs that are corroborated by market data. These are inputs other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date.
	•	Level 3 – Unobservable inputs that are not corroborated by market data and may be used with internally developed methodologies that result in management’s best estimate of fair value.
	The Company uses a market or income approach for recurring fair value measurements and endeavors to use the best information available. Accordingly, valuation techniques that maximize the use of observable inputs are favored. The assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the placement of assets and liabilities within the levels of the fair value hierarchy.
	The Company’s current asset and liability accounts contain certain financial instruments, the most significant of which are trade accounts receivables and trade payables. The Company believes the carrying values of its current assets and liabilities approximate fair value. The Company’s fair value assessment incorporates a variety of considerations, including the short-term duration of the instruments, the Company’s historical incurrence of insignificant bad debt expense and the Company’s expectation of future insignificant bad debt expense, which includes an evaluation of counterparty credit risk.
	The following table provides the assets and liabilities carried at fair value measured on a recurring basis at December 31, 2014 and 2013:
			Balance at			Quoted prices in active markets			Significant other observable inputs			Unobservable inputs
	(in millions)		December 31, 2014			(Level 1)			(Level 2)			(Level 3)
	ASSETS
	Cash and cash equivalents		$	87.9		$	87.9		$	—		$	—
	Other current assets
	Derivative asset - current		1.7			—			1.7			—
			$	89.6		$	87.9		$	1.7		$	—
	LIABILITIES
	Accrued liabilities
	Derivative liability - current		$	4.1		$	—		$	4.1		$	—
	Other liabilities
	Derivative liability - long-term		0.4			—			0.4			—
			$	4.5		$	—		$	4.5		$	—
			Balance at			Quoted prices in active markets			Significant other observable inputs			Unobservable inputs
	(in millions)		December 31, 2013			(Level 1)			(Level 2)			(Level 3)
	ASSETS
	Cash and cash equivalents		$	85.8		$	85.8		$	—		$	—
			$	85.8		$	85.8		$	—		$	—
	As of December 31, 2014 and 2013, the Company had no Level 3 fair value assets or liabilities. During the third quarter of 2012 and in conjunction with the IPO, the Company terminated the contingent consideration arrangements (margin support and earn-out) with MPC and settled all outstanding assets and liabilities by paying MPC $40 million in cash and by NT Holdings issuing a $45 million perpetual payment in kind preferred interest in NT Holdings to MPC and by the Company forgiving the $30 million margin support receivable owed by MPC to the Company. The Company recorded $104.3 million of contingent consideration losses during the year ended December 31, 2012 related to the changes in value and settlement of these arrangements. The $45 million preferred interest in NT Holdings held by MPC was redeemed during the year ended December 31, 2013.
	Prior to the settlement, the Company determined the fair value of its contingent consideration arrangements based on a probability-weighted income approach derived from financial performance estimates. The impacts of changes in the fair value of these arrangements were recorded in the statements of operations as contingent consideration (loss) income. These contingent consideration arrangements were reported at fair value using Level 3 inputs due to such arrangements not having observable market prices. The fair value of the arrangements was determined based on a Monte Carlo simulation using management projections of future period EBITDA levels. Changes in the fair value of the Company’s Level 3 contingent consideration arrangements during the year ended December 31, 2012 were due to updated financial performance estimates and are as follows:
			Margin						Net
	(in millions)		Support			Earnout			Impact
	Fair Value at December 31, 2011		$	20.2		$	(30.9	)	$	(10.7	)
	Change in fair value of remaining years		(20.2		)	(84.1		)	(104.3		)
	Settlement of contingent consideration agreements		—			115			115
	Fair Value at December 31, 2012		$	—		$	—		$	—
	The significant unobservable inputs used in the fair value measurement of the Company’s Level 3 instruments were the management projections of EBITDA. In developing these management projections, the Company used the forward market prices for various crude oil types, other feedstocks and refined products and applied its historical operating performance metrics against those forward market prices to develop its projected future EBITDA. Significant increases (decreases) in the projected future EBITDA levels would have resulted in significantly higher (lower) fair value measurements.
	The Company’s policy is to recognize transfers in and transfers out as of the actual date of the event or of the change in circumstances that caused the transfer. For the years ended December 31, 2014 and 2013, there were no transfers in or out of Levels 1, 2 or 3.
	Assets not recorded at fair value on a recurring basis, such as property, plant and equipment, intangible assets and cost method investments, are recognized at fair value when they are impaired. During the years ended December 31, 2014, 2013 and 2012 there were no adjustments to the fair value of such assets.
	The carrying value of debt, which is reported on the Company’s consolidated balance sheets, reflects the cash proceeds received upon its issuance, net of subsequent repayments. The fair value of the 2020 Secured Notes disclosed below was determined based on quoted prices in active markets (Level 1).
			December 31, 2014						December 31, 2013
	(in millions)		Carrying Amount			Fair Value			Carrying Amount			Fair Value
	2020 Secured Notes		$	354.2		$	351.3		$	275		$	291.1

Asset_Retirement_Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS
	The following table summarizes the changes in asset retirement obligations:
		Year Ended December 31,
	(in millions)	2014		2013		2012
	Asset retirement obligation balance at beginning of period	$	2.2	$	1.9	$	1.5
	Revisions of previous estimates	—		—		0.2
	Accretion expense	0.2		0.3		0.2
	Asset retirement obligation balance at end of period	$	2.4	$	2.2	$	1.9

EquityBased_Compensation

Equity-Based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity-Based Compensation	EQUITY-BASED COMPENSATION
	The Company maintains an equity-based compensation plan designed to encourage employees and directors of the Company to achieve superior performance. The current plan is maintained by the general partner of NTE LP and is referred to as the 2012 Long-Term Incentive Plan (“LTIP”). A former equity-based plan (the “NT Investor Plan”) was sponsored by members of NT Investors, the parent company of NT Holdings, and granted profit unit interests in NT Investors. All equity-based compensation expense related to both plans is recognized by the Company. The Company recognized equity-based compensation expense of $14.0 million, $7.1 million and $0.9 million for the years ended December 31, 2014, 2013 and 2012, respectively, related to these plans. This expense is included in selling, general and administrative expenses and reorganization and related costs (see Note 22) in the consolidated statements of operations and comprehensive income.
	LTIP
	Approximately 8.1 million NTE LP common units are reserved for issuance under the LTIP. The LTIP was created concurrent with the IPO and permits the award of unit options, restricted units, phantom units, distribution equivalent rights, unit appreciation rights and other awards that derive their value from the market price of NTE LP’s common units. As of December 31, 2014, approximately 0.7 million units were outstanding under the LTIP. The Company recognizes the expense on all LTIP awards ratably from the grant date until all units become unrestricted. Awards generally vest ratably over a three-year period beginning on the award's first anniversary date. Compensation expense related to these restricted units is based on the grant date fair value as determined by the closing market price on the grant date, reduced by the fair value of estimated forfeitures. For awards to employees, the Company estimates a forfeiture rate which is subject to revision depending on the actual forfeiture experience.
	As of December 31, 2014 and 2013, the total unrecognized compensation cost for LTIP restricted units was $12.1 million and $6.1 million, respectively.
	Restricted Common Units
	As of December 31, 2014, the Company had 0.4 million restricted common units outstanding. Upon vesting, these common units will no longer be restricted. All restricted common units participate in distributions on an equal basis with common units and any such distributions must be paid no later than 30 days after the distribution date to common unitholders. For restricted common unit awards outstanding at December 31, 2014, the forfeiture rates on LTIP awards ranged from zero to 30%, depending on the employee classification and the length of the award's vesting period.
	A summary of the restricted common unit activity is set forth below:
		Number of		Weighted			Weighted Average Term
		restricted common units		Average Grant			Until Maturity
		(in thousands)		Date Price			(years)
	Outstanding at December 31, 2012	6.1		$	25.69		3
	Awarded	321.9		27.02			3.5
	Cancelled	(3.5	)	28.28			—
	Vested	(17.9	)	26.38			—
	Nonvested at December 31, 2013	306.6		$	27.02		2.9
	Awarded	486.9		24.31			2
	Cancelled	(7.2	)	25.21			—
	Vested	(390.1	)	25.99			—
	Nonvested at December 31, 2014	396.2		$	24.73		1.3
	Phantom Common Units
	In 2014, the Company began issuing time-based phantom common units to key employees. As of December 31, 2014, the Company had 0.3 million phantom common units outstanding. Upon vesting, the Company may settle these units in common units or cash at the discretion of the board of directors of NTE GP, or its compensation committee. Like the restricted common units, the phantom common units participate in distributions on an equal basis with common units. However, distributions on phantom common units are accrued until the underlying units vest at which time the distributions are paid in cash. In the event that unvested phantom common units are canceled, any accrued distributions on the underlying units are forfeited by the grantee. As of December 31, 2014, the Company had $0.8 million in accrued phantom common unit distributions located in accrued liabilities in the consolidated balance sheet. For phantom common unit awards outstanding at December 31, 2014, the forfeiture rates on LTIP awards ranged from 5% to 20%, depending on the employee classification.
	A summary of the phantom common unit activity is set forth below:
		Number of		Weighted			Weighted Average Term
		phantom common units		Average Grant			Until Maturity
		(in thousands)		Date Price			(years)
	Nonvested at December 31, 2013	—		$	—		—
	Awarded	351.5		26.99			2.7
	Cancelled	(12.9	)	27.01			—
	Vested	(0.9	)	27.01			2.3
	Nonvested at December 31, 2014	337.7		$	26.99		2
	In January and February 2015, the Company issued an additional 0.7 million phantom common units to key employees and non-employee directors. These phantom units had an aggregate grant date fair value of $15.1 million and contain both time-based vesting and performance based vesting conditions expected to mature at the end of three years following at the issuance date.
	NT Investor Plan
	The NT Investor Plan was an equity participation plan which provided for the award of profit interest units in NT Investors to certain employees and independent non-employee directors of NTE LLC. Approximately 29 million profit interest units in NT Investors were reserved for issuance under the plan. The exercise price for a profit interest unit shall not be less than 100% of the fair market value of NT Investors equity units on the date of grant. Profit interest units were to vest in annual installments over a period of five years after the date of grant and expire ten years after the date of grant. Upon NT Investors meeting certain thresholds of distributions from NTE LLC and NTE LP, profit interest unit vesting would accelerate. Continued employment in any subsidiary of NT Investors is a condition of vesting and, as such, compensation expense is recognized in the Company’s financial statements based upon the fair value of the award on the date of grant. This compensation expense is a non-cash expense of the Company. The NT Investor Plan awards were satisfied by cash distributions made from NT Holdings and did not dilute cash available for distribution to the unitholders of NTE LP.
	In January 2013, upon completion of the Company’s secondary public offering of 10.7 million common units owned by NT Holdings, all outstanding and unvested profit interest units under the NT Investor Plan became immediately fully-vested. As a result, the Company accelerated all remaining unrecognized expense related to this plan resulting in a non-cash expense of $5.3 million recorded during the year ended December 31, 2013 related to this plan. This expense is included in selling, general and administrative expenses in the consolidated statements of operations and comprehensive income. No awards were issued or outstanding under this plan 2014 and no further awards will be issued from the NT Investor Plan.
	A summary of the NT Investor Plan's profit interest unit activity is set forth below:
		Number of NT Investor Profit Units		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
		(in millions)				(years)
	Outstanding at December 31, 2012	19.5		1.96		8.1
	Vested	(19.5	)	1.96
	Outstanding at December 31, 2013	—		—		—
	The estimated weighted average fair value as of the grant date for NT Investor Plan profit interest units granted during the year ended December 31, 2012, was $0.88, based upon the following assumptions:
		2012
	Expected life (years)	6.5
	Expected volatility	55.50%
	Expected dividend yield	0.00%
	Risk-free interest rate	1.40%
	The weighted average expected life for the grants was calculated using the simplified method, which defines the expected life as the average of the contractual term of the options and the weighted average vesting period. The expected volatility for the grants was based primarily on the historical volatility of a representative group of peer companies for a period consistent with the expected life of the awards.
	For the years ended December 31, 2013 and 2012, the Company recognized $5.3 million and $0.9 million, respectively, of compensation costs related to profit interest units. There was no unrecognized compensation cost for NT Investor Plan profit interest units at December 31, 2013.

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS
	Defined Contribution Plans
	The Company sponsors two qualified defined contribution plans (collectively, the “Retirement Savings Plans”) for eligible employees. Eligibility is based upon a minimum age requirement and a minimum level of service. Participants may make contributions of a percentage of their annual compensation subject to Internal Revenue Service limits. For certain participant groups, the Company provides a matching contribution at the rate of 100% of up to 6.0% of a participant’s contribution and a non-matching contribution of 3.0% of eligible compensation. For other participant groups, the Company provides a non-elective fixed annual contribution of 3.5% of eligible compensation. Total Company contributions to the Retirement Savings Plans were $7.1 million, $6.1 million and $3.7 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	Cash Balance Plan
	The Company sponsors a defined benefit cash balance pension plan (the “Cash Balance Plan”) for eligible employees. Company contributions are made to the cash account of the participants equal to 5.0% of eligible compensation. Participants’ cash accounts also receive interest credits each year based upon the average thirty-year United States Treasury bond rate published in September preceding the respective plan year. Participants become fully-vested in their accounts after three years of service.
	Retiree Medical Plan
	The Company also sponsors a plan to provide retirees with health care benefits prior to age 65 (the “Retiree Medical Plan”) for eligible employees. Eligible employees may participate in the Company’s health care benefits after retirement subject to cost-sharing features. To be eligible for the Retiree Medical Plan employees must have completed at least 10 years of service with the Company, inclusive of years of service with Marathon, and be between the ages of 55 and 65 years old.
	Funded Status and Net Period Benefit Costs
	The changes to the benefit obligation, fair value of plan assets and funded status of the Cash Balance Plan and the Retiree Medical Plan (the “Plans”) for the years ended December 31, 2014, 2013 and 2012 were as follows:
				Cash Balance Plan												Retiree Medical Plan
				Year Ended December 31,												Year Ended December 31,
	(in millions)			2014				2013				2012				2014				2013				2012
	Change in benefit obligation:
		Benefit obligation at beginning of year		$	4.6			$	2.3			$	0.5			$	2.1			$	2.4			$	—
			Service cost	2.1				1.9				1.7				0.2				0.3				0.1
			Interest cost	0.3				0.2				0.1				0.1				0.1				0.1
			Actuarial loss (gain)	0.6				0.3				0.1				0.7				(0.6		)		0.8
			Plan amendments	—				—				—				—				—				1.4
			Benefits paid	(0.6		)		(0.1		)		(0.1		)		—				(0.1		)		—
		Benefit obligation at end of year		7				4.6				2.3				3.1				2.1				2.4
	Change in plan assets:
		Fair value of plan assets at beginning of year		4.6				2.1				0.1				—				—				—
			Employer contributions	0.2				2.5				2.1				—				0.1				—
			Return on plan assets	0.1				0.1				—				—				—				—
			Benefits paid	(0.6		)		(0.1		)		(0.1		)		—				(0.1		)		—
		Fair value of plan assets at end of year		4.3				4.6				2.1				—				—				—
	Reconciliation of funded status:
		Fair value of plan assets at end of year		4.3				4.6				2.1				—				—				—
		Benefit obligation at end of year		7				4.6				2.3				3.1				2.1				2.4
		Funded status at end of year		$	(2.7	)		$	—			$	(0.2	)		$	(3.1	)		$	(2.1	)		$	(2.4	)
	At December 31, 2014 and 2013, the projected benefit obligations exceeded the fair value of the Plans’ assets by $5.8 million and $2.1 million, respectively. This unfunded obligation is classified in other liabilities on the consolidated balance sheets.
	Our cash balance plan held investments in mutual funds of $4.3 million and $4.6 million at December 31, 2014 and 2013, respectively, that were valued using level 1 inputs from the fair value hierarchy (see Note 14).
	The components of net periodic benefit cost and other amounts recognized in equity related to the Plans for the years ended December 31, 2014, 2013 and 2012 were as follows:
			Cash Balance Plan												Retiree Medical Plan
			Year Ended December 31,												Year Ended December 31,
	(in millions)		2014				2013				2012				2014				2013				2012
	Components of net periodic benefit cost:
		Service cost	$	2.1			$	1.9			$	1.7			$	0.2			$	0.3			$	0.1
		Amortization of prior service cost	—				—				—				0.1				0.2				0.1
		Interest cost	0.3				0.2				0.1				0.1				0.1				0.1
		Expected return on plan assets	(0.2		)		(0.1		)		—				—				—				—
		Net periodic benefit cost	$	2.2			$	2			$	1.8			$	0.4			$	0.6			$	0.3
	Changes recognized in other comprehensive (income) loss:
		Prior service cost addition (amortization)	$	—			$	—			$	(0.1	)		$	(0.2	)		$	(0.2	)		$	1.3
		Actuarial (gain) loss	0.7				0.3				—				0.7				(0.6		)		0.8
		Experience loss	—				—				0.1				—				—				—
		Total changes recognized in other comprehensive (income) loss	$	0.7			$	0.3			$	—			$	0.5			$	(0.8	)		$	2.1
	Assumptions
	The weighted average assumptions used to determine the Company’s benefit obligations are as follows:
		Cash Balance Plan						Retiree Medical Plan
		Year Ended December 31,						Year Ended December 31,
		2014		2013		2012		2014		2013		2012
	Discount rate	4.00%		5.00%		4.00%		4.00%		5.00%		4.00%
	Rate of compensation increase	3.00%		4.00%		4.00%		N/A		N/A		N/A
	Health care cost trend rate:
	Initial rate	N/A		N/A		N/A		7.50%		7.00%		7.50%
	Ultimate rate	N/A		N/A		N/A		5.00%		5.00%		5.00%
	Years to ultimate	N/A		N/A		N/A		5		4		5
	The weighted average assumptions used to determine the net periodic benefit cost are as follows:
		Cash Balance Plan						Retiree Medical Plan
		Year Ended December 31,						Year Ended December 31,
		2014		2013		2012		2014		2013		2012
	Discount rate	5.00%		4.00%		4.75%		5.00%		4.00%		4.75%
	Expected long-term rate of return on plan assets	4.75%		4.25%		4.50%		N/A		N/A		N/A
Rate of compensation increase	4.00%		4.00%		4.00%		N/A		N/A		N/A
Heather care cost trend rate:
Initial rate	N/A		N/A		N/A		7.00%		7.50%		7.50%
Ultimate rate	N/A		N/A		N/A		5.00%		5.00%		5.00%
Years to ultimate	N/A		N/A		N/A		4		5		5
The assumptions used to determine of the Company’s obligations and benefit cost are based upon management’s best estimates as of the annual measurement date. The discount rate utilized was based upon bond portfolio curves over a duration similar to the Cash Balance Plan’s and Retiree Medical Plan’s respective expected future cash flows as of the measurement date. The expected long-term rate of return on plan assets is the weighted average rate of earnings expected of the funds invested or to be invested based upon the targeted investment strategy for the plan. The assumed average rate of compensation increase is the average annual compensation increase expected over the remaining employment periods for the participating employees.
Contributions, Plan Assets and Estimated Future Benefit Payments
Employer contributions to the Cash Balance Plan of $0.2 million, $2.5 million and $2.1 million were made during the years ended December 31, 2014, 2013 and 2012, respectively. These contributions were invested into equity and bond mutual funds and money market funds which are deemed Level 1 assets as described in Note 14. The Company expects funding requirements of approximately $5.1 million during the year ending December 31, 2015.
At December 31, 2014, anticipated benefit payments to participants from the Plans in future years are as follows:
(in millions)	Cash Balance Plan				Retiree Medical Plan
2015	$	0.3			$	0.1
2016	0.4				0.1
2017	0.5				0.1
2018	0.6				0.1
2019	0.8				0.1
2020-2024	6.5				1

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	SUPPLEMENTAL CASH FLOW INFORMATION
	Supplemental cash flow information is as follows:
		Year Ended December 31,
	(in millions)	2014		2013		2012
	Net cash from operating activities included:
	Interest paid	$	22.5	$	26.7	$	32.9
	Income taxes paid	5		3.7		—
	Noncash investing and financing activities include:
	Capital expenditures included in accounts payable	$	2.9	$	10.2	$	1.2
	PP&E derecognized in sale leaseback	—		—		(4.7		)
	PP&E additions resulting from a capital lease	1.7		1.2		1

Leasing_Arrangements

Leasing Arrangements	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Leasing Arrangements	LEASING ARRANGEMENTS
	Concurrent with the Marathon Acquisition (see Note 5), certain Marathon assets (including real property interests and land related to 135 of the SuperAmerica convenience stores and the SuperMom’s bakery) were sold to a third party equity real estate investment trust. In connection with the closing of the Marathon Acquisition, the Company assumed the leasing of these properties from the real estate investment trust on a long-term basis. All stores owned at the conclusion of these transactions were sold and leased back from the equity real estate investment trust. As of December 31, 2014, 133 of the SuperAmerica convenience stores and the SuperMom’s Bakery remain under the lease with the equity real estate investment trust.
	In accordance with ASC Topic 840 “Sale Leaseback Transactions,” the Company determined that subsequent to the sale, it had a continuing involvement for a portion of these property interests due to potential environmental obligations or due to subleasing arrangements. For these respective properties, the fair value of the assets and the related lease obligation will remain on the Company’s consolidated balance sheet until the end of the lease term or until the continuing involvement is resolved. The assets are included in property, plant and equipment and are being depreciated over their remaining useful lives. The lease payments relating to these property interests are recognized as interest expense. Subsequent to the initial transaction, the Company’s continuing involvement ended for a subset of these stores and, as such, the related fair value of the assets and the lease obligation for these stores have been removed from the Company’s consolidated balance sheet.
	The remainder of properties sold to the third party real estate investment trust are treated as operating leases. The Company also leases a variety of facilities and equipment under other operating leases, including land and building space, office equipment, vehicles, rail tracks for storage of rail tank cars near the refinery and numerous rail tank cars. Many of our operating leases have renewal options at various future dates and some of our leases have escalation clauses which are indexed to CPI or other inflation related measures.
	Future minimum commitments for operating lease obligations having an initial or remaining non-cancelable lease terms in excess of one year are as follows:
	(in millions)	Capital Leases			Operating Leases		Total Leases
	2015	$	1.2		$	22.7	$	23.9
	2016	1.2			23.4		$	24.6
	2017	1			22.7		$	23.7
	2018	0.9			22.2		$	23.1
	2019	0.9			21.8		$	22.7
	Thereafter	9.2			133		142.2
	Total	$	14.4		$	245.8	$	260.2
	Less: amount representing interest	$	(9.6	)	$	—	$	(9.6	)
	Present value of net minimum lease payments	$	4.8		$	245.8	$	250.6
	Rental expense was $25.4 million, $24.0 million, $23.5 million for the years ended December 31, 2014, 2013 and 2012, respectively.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES
	The Company is the subject of, or party to, contingencies and commitments involving a variety of matters. Certain of these matters are discussed below. The ultimate resolution of these contingencies could, individually or in the aggregate, be material to the Company’s consolidated financial statements.
	Environmental Matters
	The Company is subject to federal, state, local and foreign laws and regulations relating to the environment. These laws generally provide for control of pollutants released into the environment and require responsible parties to undertake remediation of hazardous waste disposal sites. Penalties may be imposed for noncompliance. At December 31, 2014 and 2013, accruals for remediation and closure obligations totaled $8.7 million and $1.5 million, respectively. Of the $8.7 million and $1.5 million accrued, $2.9 million and $1.5 million are recorded on a discounted basis as of December 31, 2014 and 2013, respectively. These discounted liabilities are expected to be settled over at least the next 23 years. At December 31, 2014, the estimated future cash flows to settle these discounted liabilities totaled $3.5 million and are discounted at a rate of 2.55%. Receivables for recoverable costs from the state, under programs to assist companies in clean-up efforts related to underground storage tanks at retail marketing outlets, and others were $0.2 million and $0.1 million at December 31, 2014 and 2013, respectively. Costs associated with environmental remediation are recorded in direct operating expenses in the statement of operations.
	On June 3, 2014, SPPR was issued a National Pollutant Discharge Elimination Permit/State Disposal System Permit by the Minnesota Pollution Control Agency ("MPCA") relating to its upgraded wastewater treatment plant at its St. Paul Park Refinery. This permit required the refinery to conduct additional testing of its remaining lagoon. The testing was completed in the fourth quarter of 2014 and, following our review of the test results and additional discussions with the MPCA, we now regard the likelihood of future remediation costs related to the lagoon as probable. At December 31, 2014, we estimate the remediation costs to be approximately $5.8 million subject to further engineering and methodology studies. Some or all of this cost cost may be recoverable from Marathon Petroleum under an agreement entered into in connection with our December 2010 acquisition of the St. Paul Park Refinery, among other assets, from Marathon. However, at December 31, 2014 it is unclear how much, if any, of our future costs may be reimbursed by Marathon, and as such, we have not at this time recognized any receivable for this matter.
	Future estimated cash outflows to remediate environmental matters are as follows:
	(in millions)	Groundwater Contamination			Wastewater Lagoon		Total
	2015	$	0.5		$	5.8	$	6.3
	2016	0.3			—		$	0.3
	2017	0.2			—		$	0.2
	2018	0.2			—		$	0.2
	2019	0.2			—		$	0.2
	Thereafter	2.1			—		$	2.1
	Total	$	3.5		$	5.8	$	9.3
	Less: amount representing interest	$	(0.6	)	$	—	$	(0.6	)
	Present value of estimated future cash flows	$	2.9		$	5.8	$	8.7
	It is not presently possible to estimate the ultimate amount of all remediation costs that might be incurred by the Company or the penalties that may be imposed. Furthermore, environmental remediation costs may vary from estimates for which a liability has been recorded either in accrued liabilities or other liabilities in the balance sheet because of changes in laws, regulations and their interpretation; additional information on the extent and nature of site contamination; and improvements in technology.
	Franchise Agreements
	In the normal course of its business, SAF enters into ten-year license agreements with the operators of franchised SuperAmerica brand retail outlets. These agreements obligate SAF or its affiliates to provide certain services including information technology support, maintenance, credit card processing and signage for specified monthly fees.
	Guarantees
	Certain agreements related to assets sold in the normal course of business contain performance and general guarantees, including guarantees regarding inaccuracies in representations, warranties, covenants and agreements, and environmental and general indemnifications that require the Company to perform upon the occurrence of a triggering event or condition. These guarantees and indemnifications were part of the normal course of selling assets. The Company has assumed these guarantees and indemnifications upon the Marathon Acquisition. However, in certain cases, MPC LP has also provided an indemnification in favor of the Company.
	The Company is not typically able to calculate the maximum potential amount of future payments that could be made under such contractual provisions because of the variability inherent in the guarantees and indemnities. Most often, the nature of the guarantees and indemnities is such that there is no appropriate method for quantifying the exposure because the Company has little or no past experience associated with the underlying triggering event upon which a reasonable prediction of the outcome can be based. The Company is not currently making any payments relating to such guarantees or indemnifications.

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION
	The Company has two reportable operating segments: Refining and Retail. Each of these segments is organized and managed based upon the nature of the products and services they offer. The segment disclosures reflect management’s current organizational structure.
	•	Refining – operates the St. Paul Park, Minnesota refinery, terminal, NTOT and related assets, and includes the Company’s interest in MPL and MPL Investments, and
	•	Retail – operates 165 convenience stores primarily in Minnesota and Wisconsin. The retail segment also includes the operations of NTB and SAF.
	Operating results for the Company’s operating segments are as follows:
	(in millions)
	Year ended December 31, 2014		Refining		Retail		Other			Total
	Revenues
	Customer		$	4,165.60	$	1,390.40	$	—		$	5,556.00
	Intersegment		932.1		—		—			932.1
	Segment revenues		5,097.70		1,390.40		—			6,488.10
	Elimination of intersegment revenues		—		—		(932.1		)	(932.1		)
	Total revenues		$	5,097.70	$	1,390.40	$	(932.1	)	$	5,556.00
	Income (loss) from operations		$	303.5	$	22.9	$	(51.1	)	$	275.3
	Income from equity method investment		$	2.2	$	—	$	—		$	2.2
	Depreciation and amortization		$	33.7	$	7.3	$	0.9		$	41.9
	Capital expenditures		$	35.4	$	8.8	$	0.6		$	44.8
	(in millions)
	Year ended December 31, 2013		Refining		Retail		Other			Total
	Revenues
	Customer		$	3,520.20	$	1,459.00	$	—		$	4,979.20
	Intersegment		1,015.80		—		—			1,015.80
	Segment revenues		4,536.00		1,459.00		—			5,995.00
	Elimination of intersegment revenues		—		—		(1,015.8		)	(1,015.8		)
	Total revenues		$	4,536.00	$	1,459.00	$	(1,015.8	)	$	4,979.20
	Income (loss) from operations		$	263.1	$	15.2	$	(32.2	)	$	246.1
	Income from equity method investment		$	10	$	—	$	—		$	10
	Depreciation and amortization		$	30.4	$	7.1	$	0.6		$	38.1
	Capital expenditures		$	88.7	$	7.7	$	0.2		$	96.6
	(in millions)
	Year ended December 31, 2012		Refining		Retail		Other			Total
	Revenues
	Customer		$	3,171.50	$	1,482.40	$	—		$	4,653.90
	Intersegment		1,041.10		—		—			1,041.10
	Segment revenues		4,212.60		1,482.40		—			5,695.00
	Elimination of intersegment revenues		—		—		(1,041.1		)	(1,041.1		)
	Total revenues		$	4,212.60	$	1,482.40	$	(1,041.1	)	$	4,653.90
	Income (loss) from operations		$	705.6	$	8.7	$	(145.0	)	$	569.3
	Income from equity method investment		$	12.3	$	—	$	—		$	12.3
	Depreciation and amortization		$	25.4	$	6.6	$	1.2		$	33.2
	Capital expenditures		$	24.2	$	4.6	$	2.1		$	30.9
	Intersegment sales from the refining segment to the retail segment consist primarily of sales of refined products which are recorded based on contractual prices that are market-based. Revenues from external customers are nearly all in the United States.
	Total assets by segment were as follows:
	(in millions)		Refining		Retail		Corporate/Other			Total
	At December 31, 2014		$	932.9	$	134	$	113.5		$	1,180.40
	At December 31, 2013		$	875.6	$	138.2	$	104		$	1,117.80
	The Company's equity method investment in MPL is included in the refining segment's assets and had a carrying value of $80.7 million and $86.2 million at December 31, 2014 and 2013, respectively. See Note 8 for further information on the Company’s equity method investment.
	Total assets for the refining and retail segments exclude all intercompany balances. All cash and cash equivalents are included as corporate/other assets. All property, plant and equipment are located in the United States.

Reorganization_and_Related_Cos

Reorganization and Related Costs (Notes)	12 Months Ended
	Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Reorganization and Related Costs	22. REORGANIZATION AND RELATED COSTS
	During the first quarter of 2014, the Company initiated a plan that included the relocation of its corporate offices from Ridgefield, Connecticut to Tempe, Arizona and the reorganization of various positions within the Company, primarily among senior management. In relation to this reorganization plan, it was determined during the year ended December 31, 2014 that certain employees of the Company would be terminated. The Company recognized $12.9 million of expense during the year ended December 31, 2014, which included compensation related to the severance of employment and the acceleration of unvested equity based compensation. These costs are recognized in the reorganization and related costs line within the consolidated statements of operations and comprehensive income. All reorganization and related costs are recognized in the Other segment. Substantially all reorganization costs associated with the corporate office relocation were fully recognized at December 31, 2014. As of December 31, 2014, the Company had $0.8 million in unpaid reorganization expenses included in the accrued liabilities line item of the consolidated balance sheets, which will be paid from 2014 through 2016.
	(in millions)	For the year ended December 31, 2014
	Reorganization and related costs incurred during period	$	12.9
	Less: non-cash equity based awards with accelerated vesting	(4.8		)
	Cash payments made to severed employees	(7.3		)
	Ending liability for cash portion of reorganization costs	$	0.8

Supplementary_Quarterly_Financ

Supplementary Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Supplementary Quarterly Financial Information (Unaudited)	SUPPLEMENTARY QUARTERLY FINANCIAL INFORMATION (UNAUDITED)
	(in millions, except per unit data)		First Quarter		Second Quarter		Third Quarter		Fourth Quarter		Total
	2014
		Revenue	$	1,346.30	$	1,602.50	$	1,547.40	$	1,059.80	$	5,556.00
		Operating income	77.8		65.6		104.8		27.1		275.3
		Net income	71.5		57.9		96.2		16		241.6
		Earnings per common unit - basic	$	0.77	$	0.62	$	1.04	$	0.17	$	2.61
		Earnings per common unit - diluted	$	0.77	$	0.62	$	1.04	$	0.17	$	2.61
	2013
		Revenue	$	1,115.00	$	1,131.20	$	1,440.90	$	1,292.10	$	4,979.20
		Operating income	132.2		52.6		27.5		33.8		246.1
		Net income	119.4		63.9		27.2		20.6		231.1
		Earnings per common unit - basic and diluted	$	1.3	$	0.7	$	0.3	$	0.22	$	2.51

Summary_of_Principal_Accountin1

Summary of Principal Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Principles of Consolidation [Policy Text Block]	Principles of Consolidation
	NTE LP is a Delaware limited partnership that was established as Northern Tier Energy, Inc. on October 24, 2011 and was subsequently converted into NTE LP as of June 4, 2012. On July 31, 2012, NTE LP closed its IPO whereby it sold 18,687,500 limited partnership units to the public. In connection with the closing of the IPO, NT Holdings contributed all of its membership interests in NTE LLC to NTE LP in exchange for 54,844,500 common units and 18,383,000 PIK units, which were subsequently converted into common units, of NTE LP (see Note 3). Upon the closing of the IPO, the consolidated historical financial statements of NTE LLC became the historical financial statements of NTE LP. NTE LP consolidates all accounts of NTE LLC and its direct subsidiaries.
	The Company’s common equity interest in MPL is accounted for using the equity method of accounting in accordance with the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”) Topic 323. Equity income from MPL represents the Company’s proportionate share of net income available to common equity owners generated by MPL.
	The equity method investment is assessed for impairment whenever changes in facts or circumstances indicate a loss in value has occurred. When the loss is deemed to be other than temporary, the carrying value of the equity method investment is written down to fair value, and the amount of the write-down is included in net income. See Note 8 for further information on the Company’s equity method investment.
	MPL Investments owns all of the preferred membership units of MPL. This investment in MPL Investments, which provides the Company no significant influence over MPL Investments, is accounted for as a cost method investment. The investment in MPL Investments is carried at a value of $6.8 million as of both December 31, 2014 and 2013 and is included in other noncurrent assets within the consolidated balance sheets.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates
	The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the respective reporting periods. Actual results could differ from those estimates.
Segment Reporting, Policy [Policy Text Block]	Operating Segments
	The Company has two reportable operating segments; Refining and Retail (see Note 21 for further information on the Company’s operating segments). The Refining and Retail operating segments consist of the following:
	•	Refining – operates the St. Paul Park, Minnesota refinery, terminal and related assets, NTOT and includes the Company’s interest in MPL and MPL Investments, and
	•	Retail – operates 165 convenience stores primarily in Minnesota and Wisconsin. The retail segment also includes the operations of SAF and NTB.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents
	The Company considers all highly liquid investments with maturities of three months or less from the date of purchase to be cash equivalents.
Trade and Other Accounts Receivable, Policy [Policy Text Block]	Receivables and Allowance for Doubtful Accounts
	Receivables of the Company primarily consist of customer accounts receivable. The accounts receivable are due from a diverse base including companies in the petroleum industry, airlines and governmental entities. The allowance for doubtful accounts is reviewed regularly for collectability. All customer receivables are recorded at the invoiced amounts and generally do not bear interest. When it becomes probable the receivable will not be collected, the balances for customer receivables are charged directly to bad debt expense. The allowance for doubtful accounts was $0.2 million as of both December 31, 2014 and 2013.
Inventory, Policy [Policy Text Block]	Inventories
	Crude oil, refined product and other feedstock and blendstock inventories are carried at the lower of cost or market ("LCM"). Cost is determined principally under the last-in, first-out (“LIFO”) valuation method to reflect a better matching of costs and revenues for refining inventories. Costs include both direct and indirect expenditures incurred in bringing an item or product to its existing condition and location. Ending inventory costs in excess of market value are written down to net realizable market values and charged to cost of sales in the period recorded. In subsequent periods, a new LCM determination is made based upon current circumstances. The Company has LIFO pools for crude oil and other feedstocks and for refined products in its Refining segment and a LIFO pool for refined products inventory held by the retail stores in its Retail segment. Retail merchandise inventory is valued using the average cost method.
Property, Plant and Equipment, Policy [Policy Text Block]	Property, Plant and Equipment
	Property, plant and equipment is recorded at cost and depreciated on a straight-line basis over the estimated useful lives of the assets. Such assets or asset groups are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the expected undiscounted future cash flows from the use of the asset and its eventual disposition is less than the carrying amount of the asset, an impairment loss is recognized based on the fair value of the asset.
	When property, plant and equipment depreciated on an individual basis is sold or otherwise disposed of, any gains or losses are reported in the consolidated statements of operations. Gains on the disposal of property, plant and equipment are recognized when earned, which is generally at the time of sale. If a loss on disposal is expected, such losses are generally recognized when the assets are classified as held for sale.
	Expenditures for routine maintenance and repair costs are expensed when incurred. Refinery process units require periodic major maintenance and repairs that are commonly referred to as “turnarounds.” The required frequency of the maintenance varies by unit, but generally is every two to six years depending on the processing unit involved. Turnaround costs are expensed as incurred.
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]	Intangible Assets
	Intangible assets primarily include a retail marketing trade name and franchise agreements. These assets have an indefinite life and therefore are not amortized, but rather are tested for impairment annually or when events or changes in circumstances indicate that the fair value of the intangible asset has been reduced below carrying value. If the estimated fair value is less than the carrying amount of the asset, an impairment loss is recognized based on the estimated fair value of the asset. Significant assumptions in determining the estimated fair value of the indefinite lived intangibles include projected store growth, estimated market royalty rates, market growth rates and the estimated discount rate.
Renewable Identification Numbers [Policy Text Block]	Renewable Identification Numbers
	The Company is subject to obligations to generate or purchase Renewable Identification Numbers ("RINs") required to comply with the Renewable Fuels Standard. The Company's overall RINs obligation is based on a percentage of domestic shipments of on-road fuels as established by the Environmental Protection Agency ("EPA"). To the degree the Company is unable to blend the required amount of biofuels to satisfy our RINs obligation, RINs must be purchased on the open market to avoid penalties and fines. The Company records its RINs obligation on a net basis in accrued liabilities when its RINs liability is greater than the amount of RINs earned and purchased in a given period and in other current assets when the amount of RINs earned and purchased is greater than the RINs liability.
Debt, Policy [Policy Text Block]	Financing Costs
	Financing origination fees on the Company's senior secured notes, ABL Facility and sales-leaseback transaction are deferred and classified within other assets on the consolidated balance sheets. Amortization is provided on a straight-line basis over the term of the agreement, which approximates the effective interest method.
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition
	Revenues are recognized when products are shipped or services are provided to customers, title is transferred, the sales price is fixed or determinable and collectability is reasonably assured. Revenues are recorded net of discounts granted to customers. Shipping and other transportation costs billed to customers are presented on a gross basis in revenues and cost of sales.
	Nonmonetary product exchanges and certain buy/sell crude oil transactions which are entered into in contemplation one with another are included on a net cost basis in cost of sales. The Company also enters into agreements to purchase and sell crude oil to third parties and certain of these activities are recorded on a gross basis.
	Prior to the fourth quarter of 2014, the Company maintained a crude oil supply and logistics agreement with JPM CCC pursuant to which JPM CCC assisted the Company in the purchase of substantially all of its crude oil needs for the refinery. As discussed in Note 7, JPM CCC and the Company mutually agreed to terminate this agreement. In the fourth quarter of 2014, subsequent to the termination of this agreement, the Company has significantly increased its crude procurement activities and related exchange and buy/sell activity to manage the volumes, grade, timing, and locations of such crude. Such activities are similar to the buy/sell crude oil transactions noted above and are recorded net in cost of sales.
Cost of Sales, Policy [Policy Text Block]	Cost of Sales
	Cost of sales in the consolidated statements of operations and comprehensive income excludes depreciation and amortization of refinery assets and the direct labor and overhead costs related to the operation of the refinery. These costs are included in the consolidated statements of operations and comprehensive income in the depreciation and amortization and direct operating expenses line items, respectively.
Excise Taxes Policy [Text Block]	Excise Taxes
	The Company is required by various governmental authorities, including federal and state, to collect and remit taxes on certain products. Such taxes are presented on a gross basis in revenue and cost of sales in the consolidated statements of operations. These taxes totaled $396.4 million, $316.4 million and $300.1 million for the years ended December 31, 2014, 2013 and 2012, respectively.
Refined Product Exchanges Policy [Text Block]	Product Exchanges
	The Company enters into exchange contracts whereby it agrees to deliver a particular quantity and quality of crude oil or refined products at a specified location and date to a particular counterparty and to receive from the same counterparty a particular quantity and quality of crude oil or refined products at a specified location on the same or another specified date. The exchange receipts and deliveries are nonmonetary transactions, with the exception of associated grade or location differentials that are settled in cash. These transactions are recorded net in cost of sales because they involve the exchange of inventories held in the ordinary course of business to facilitate sales to customers or delivery of feedstocks to our refinery. The exchange transactions are recognized at the carrying amount of the inventory transferred plus or minus any cash settlement due to grade or location differentials.
Derivatives, Reporting of Derivative Activity [Policy Text Block]	Derivative Financial Instruments
	The Company is exposed to earnings and cash flow volatility based on the timing and change in refined product prices and crude oil prices. To manage these risks, the Company may use derivative instruments associated with the purchase or sale of crude oil and refined products. Crack spread futures and swap contracts may be used to hedge the volatility of refining margins. The Company may also use futures contracts to manage price risks associated with inventory quantities above or below target levels. All derivative instruments are recorded in the consolidated balance sheet at fair value and are classified depending on the maturity date of the underlying contracts. Changes in the fair value of its contracts are accounted for by marking them to market and recognizing any resulting gains or losses in the statements of operations. Gains and losses from derivative activity specific to the mitigation on inventory quantities are included within cost of sales. Gains and losses from derivative activity specific to the risk mitigation on the crack spread futures and swap derivatives are included within gains (losses) on derivative activities. Derivative gains and losses are reported as operating activities within the consolidated statements of cash flows.
	We enter into crude oil forward contracts to facilitate the supply of crude oil to the refinery. These contracts may qualify for the normal purchases and normal sales exception because we physically receive and deliver the crude oil under the contracts and when we enter into these contracts, the quantities are expected to be used or sold over a reasonable period of time in the normal course of business. These transactions are reflected in the period that delivery of the crude oil takes place.
Advertising Costs, Policy [Policy Text Block]	Advertising
	The Company expenses the costs of advertising as incurred. Advertising expense was $2.3 million, $2.0 million and $1.5 million for the years ended December 31, 2014, 2013 and 2012, respectively.
Asset Retirement Obligations, Policy [Policy Text Block]	Asset Retirement Obligations
	The fair value of asset retirement obligations is recognized in the period in which the obligations are incurred if a reasonable estimate of fair value can be made. Conditional asset retirement obligations for removal and disposal of fire-retardant material from certain refining assets have been recognized. The amounts recorded for such obligations are based on the most probable current cost projections. Asset retirement obligations have not been recognized for the removal of materials and equipment from or the closure of certain refinery, pipeline, terminal and retail marketing assets because the fair value cannot be reasonably estimated since the settlement dates of the obligations are indeterminable. Current inflation rates and credit-adjusted-risk-free interest rates are used to estimate the fair value of asset retirement obligations. Depreciation of capitalized asset retirement costs and accretion of asset retirement obligations are recorded over time. Depreciation is determined on a straight-line basis, while accretion escalates over the lives of the assets. See further information on our asset retirement obligations in Note 15.
Environmental Costs, Policy [Policy Text Block]	Environmental Costs
	Environmental expenditures are capitalized if the costs mitigate or prevent future contamination or if the costs improve environmental safety or efficiency of the existing assets. The Company provides for remediation costs and penalties when the responsibility to remediate is probable and the amount of associated costs can be reasonably estimated. The timing of remediation accruals coincides with completion of feasibility studies, investigations or the commitment to a formal plan of action. Environmental liabilities are difficult to assess and estimate due to uncertainties related to the magnitude of possible remediation and the timing of such remediation. Such estimates are subject to change due to many factors, including the identification of new sites requiring remediation, changes in environmental laws and regulations and their interpretation, additional information related to the extent and nature of remediation efforts and potential improvements in remediation technologies. Remediation liabilities are accrued based on estimates of known environmental exposure and are discounted when the estimated amounts are reasonably fixed and determinable. If recoveries of remediation costs from third parties are probable, a receivable is recorded and is discounted to net present value when the estimated amount is reasonably fixed and determinable.
Pension and Other Postretirement Plans, Pensions, Policy [Policy Text Block]	Defined Benefit Plans
	The Company has a cash balance plan and a retiree medical plan that are considered defined benefit plans. Expenses and liabilities related to defined benefit plans are determined on an actuarial basis and are affected by the market value of plan assets, estimates of the expected return on plan assets, and assumed discount rates and demographic data.
	Cash balance and retiree medical plan expenses and liabilities are determined based on actuarial valuations. Inherent in these valuations are key assumptions including discount rates, future compensation increases, expected return on plan assets, health care cost trends, and demographic data. Changes in our actuarial assumptions are primarily influenced by factors outside of our control and could have a significant effect on our pension and retiree medical liabilities and costs. See further information on our plans in Note 17.
Compensation Related Costs, Policy [Policy Text Block]	Equity-Based Compensation
	The Company recognizes compensation expense for equity-based awards issued over the requisite service period. Equity-based compensation costs are measured at the date of grant, based on the fair value of the award. In 2014, the Company began awarding phantom common units which, at the discretion of the board of directors of our general partner, may be settled in either cash or the Company's common units. The first tranche of phantom unit vesting occurred in January 2015 and was settled in common units. We anticipate that the remaining unvested phantom units will ultimately be satisfied with common units and have therefore classified the accrual of the service cost as equity. However, if our general partner's board elects to settle the phantom units with cash, it could cause us to remeasure the fair value of those awards resulting in an adjustment to earnings for the cumulative difference between the fair value at the date of grant and date of the remeasurement.
Income Tax, Policy [Policy Text Block]	Income Taxes
	Effective August 1, 2012, NTRH elected to be treated as a corporation for income tax purposes in order to preserve the MLP tax status of NTE LP. As such, the Company has recorded deferred tax assets and deferred tax liabilities related to NTRH as of the election date. Additionally, the Company recorded current period income taxes for all periods subsequent to August 1, 2012 (see Note 6) at the NTRH level. Prior to August 1, 2012, all of the Company’s income was derived from subsidiaries which were limited liability companies and were therefore pass-through entities for federal income tax purposes. As a result, the Company did not incur federal income taxes prior to this date. The Company’s policy is to recognize interest related to any underpayment of taxes as interest expense and any penalties as administrative expenses.
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Income
	The Company has unrecognized prior service cost related to its defined benefit cash balance plan as of December 31, 2014, 2013 and 2012 and unrecognized actuarial losses and prior service cost related to its retiree medical plan as of December 31, 2014 and 2013 (see Note 17). The accumulated unrecognized costs related to these plans amount to $3.2 million and $2.0 million as of December 31, 2014 and 2013, respectively. These gains/(losses) of $(1.2) million, $0.5 million and $(2.1) million were recognized directly to equity as an element of other comprehensive income (loss) in the years ended December 31, 2014, 2013 and 2012, respectively.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Concentrations of Risk
	The Company is exposed to credit risk in the event of nonpayment by customers. The creditworthiness of customers is subject to continuing review. No single non-related party customer accounts for more than 10% of annual revenues.
	Crude oil is the principal raw material for the Company and the majority of the crude oil processed is delivered to the refinery through a pipeline that is owned by MPL, a related party. A prolonged disruption of that pipeline’s operations would materially impact the Company’s ability to economically obtain raw materials.
	The Company is exposed to concentrated geographical risk as most of its operations are conducted in the Upper Great Plains of the United States.
Reclassifications [Policy Text Block]	Reclassifications
	Certain reclassifications have been made to the prior-year financial information in order to conform to the Company’s current presentation, which is intended to conform with Western Refining's presentation. The following reclassifications have been made:
	Derivatives
	Related to our derivative activities, a $7.4 million net gain and a $1.7 million net loss from derivative activity not related to our crack spread hedges have been reclassified from gains (losses) from derivative activities to cost of sales for the years ended December 31, 2013 and 2012, respectively, within the consolidated statements of operations and comprehensive income.
	Income from equity method investment
	Income from our equity method investment in MPL has been reclassified from other (income) loss, net to a separate line titled income from equity method investment. The amount of this reclassification was income of $10.0 million and $12.3 million for the years ended December 31, 2013 and 2012, respectively.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements
	In April 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-08, which updated the guidance in ASC Topic 205, “Presentation of Financial Statements”, and ASC Topic 360, “Property, Plant and Equipment.” This ASU raises the threshold for a disposal to qualify as discontinued operations and requires new disclosures for individual material disposal transactions that do not meet the definition of a discontinued operation.  Under the new standard, companies report discontinued operations when they have a disposal that represents a strategic shift that has or will have a major impact on operations or financial results.  This update will be applied prospectively and is effective for annual periods, and interim periods within those years, beginning after December 15, 2014.  Early adoption is permitted provided the disposal was not previously disclosed.  The adoption of this guidance is not expected to have a material impact on our results of operations, cash flows or financial position.
	In May 2014, the FASB issued ASU No. 2014-09 “Revenue from Contracts with Customers,” which provides guidance for revenue recognition. The standard’s core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This guidance will be effective for our financial statements in the annual period beginning after December 15, 2016. We are evaluating the effect of adopting this new accounting guidance we do not expect adoption will have a material impact on our results of operations, cash flows or financial position.

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense
			Year Ended December 31,
	(in millions)		2014				2013				2012
	Current tax expense		$	4.5			$	3.3			$	—
	Deferred tax expense		$	2.6			$	0.9			$	9.8
	Income tax provision		$	7.1			$	4.2			$	9.8
Schedule of Effective Income Tax Rate Reconciliation	The following is a reconciliation of income tax expense to income taxes computed by applying the applicable statutory federal income tax rate of 35% to income before income taxes for the applicable periods:
			Year Ended December 31,
	(in millions)		2014				2013				2012
	Federal statutory rate applied to income before taxes		$	87			$	82.4			$	72.6
	Taxes on earnings attributable to flow-through entities		(81.0		)		(78.6		)		(71.6		)
	State and local income taxes, net of federal income tax effects		1				0.9				—
	Initial charge upon NTRH's election to be treated as a corporation		—				—				8
	Work opportunity tax credit		(0.3		)		(0.6		)		—
	Other, net		0.4				0.1				0.8
	Income tax provision		$	7.1			$	4.2			$	9.8
Schedule of Deferred Tax Assets and Liabilities	The net deferred tax assets (liabilities) as of December 31, 2014 and 2013 consisted of the following components:
					December 31,
	(in millions)				2014				2013
	Deferred tax assets:
		Lease financing obligations			2.4				2.6
		Customer loyalty accrual			0.9				0.9
		Other			0.8				1.1
	Total deferred taxes, net				4.1				4.6
	Deferred tax liabilities:
		Accelerated depreciation			$	(5.4	)		$	(3.4	)
		Intangible assets			(11.8		)		(11.7		)
		Other			(0.2		)		(0.2		)
	Deferred tax liabilities				(17.4		)		(15.3		)
					$	(13.3	)		$	(10.7	)

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Schedule of Inventories
		December 31,
	(in millions)	2014			2013
	Crude oil and refinery feedstocks	$	137.5		$	29.4
	Refined products	150			106.7
	Merchandise	22.3			22.6
	Supplies and sundry items	15.9			14.8
		325.7			173.5
	Lower of cost or market inventory reserve	(73.6		)	—
	Total	$	252.1		$	173.5

Equity_Method_Investment_Table

Equity Method Investment (Tables)	12 Months Ended
	Dec. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	Summarized financial information for MPL is as follows:
				Year Ended December 31,
	(in millions)			2014		2013		2012
	Revenues			$	184.7	$	161.9	$	153.6
	Operating costs and expenses			141.3		74.5		52.7
	Income from operations			43.4		68.2		82.1
	Net income			22.8		68.2		82.1
	Net income available to MPL common members			13.1		58.6		72.4
				December 31,
	(in millions)			2014		2013
	Balance sheet data:
		Current assets		$	9.6	$	26.1
		Noncurrent assets		450.7		462.9
			Total assets	$	460.3	$	489
		Current liabilities		$	21.9	$	19.8
		Noncurrent liabilities		—		—
			Total liabilities	$	21.9	$	19.8
		Members capital		$	438.4	$	469.2

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Major classes of property, plant and equipment (“PP&E”) consisted of the following:
		Estimated	December 31,
	(in millions)	Useful Lives	2014			2013
	Land		$	9		$	9
	Retail stores and equipment	2 - 22 years	65.7			54.9
	Refinery and equipment	5 - 24 years	444.6			403.5
	Buildings and building improvements	25 years	10.2			8.9
	Software	5 years	18.8			18.6
	Vehicles	5 years	4.7			4.7
	Other equipment	2 - 7 years	9.1			8.5
	Precious metals		10.2			10.2
	Assets under construction		12.6			26.3
			584.9			544.6
	Less: Accumulated depreciation		(139.1		)	(98.4		)
	Property, plant and equipment, net		$	445.8		$	446.2

Derivatives_Tables

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments
		December 31,
		2014			2013
		(in thousands of barrels or barrels of oil equivalent)
	Open commodity hedging instruments:
	Crude oil and refined product futures and swaps, net short positions	(124	)		—
	Natural gas swaps, net long positions	617			—
	The information below presents the notional volume of outstanding contracts by type of instrument and year of maturity at December 31, 2014:
		Notional Contract Volumes by Year of Maturity
		2014			2015
		(in thousands of barrels or barrels of oil equivalent)
	Open commodity hedging instruments:
	Crude oil and refined product futures and swaps, net short positions	(124	)		—
	Natural gas swaps, net long positions	419			198
Recognized Gains and Losses on Derivatives	Recognized gains and losses on derivatives were as follows:
			Year Ended December 31,
	(in millions)		2014				2013				2012
	Gain (loss) on the change in fair value of outstanding derivatives		$	(2.8	)		$	41.6			$	68
	Settled derivative gains (losses)		12.4				(18.1		)		(339.4		)
	Total recognized gain (loss)		$	9.6			$	23.5			$	(271.4	)
	Gain (loss) recognized in Cost of sales		$	9.6			$	7.4			$	(1.7	)
	Gain (loss) recognized in Gains (losses) from derivative activities		—				16.1				(269.7		)
	Total recognized net gain (loss) on derivatives		$	9.6			$	23.5			$	(271.4	)
Fair Value Amounts of Outstanding Derivative Instruments	The following table summarizes the fair value amounts of the Company’s outstanding derivative instruments by location on the balance sheet as of December 31, 2014 and 2013:
					December 31,
	(in millions)		Balance Sheet Classification		2014				2013
	Commodity swaps and futures		Other current assets		$	1.7			$	—
	Commodity swaps and futures		Accrued liabilities		(4.1		)		—
	Commodity swaps and futures		Other liabilities		$	(0.4	)		$	—
	Net asset (liability) position				$	(2.8	)		$	—

Equity_Tables

Equity (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Distributions Paid During or Pertaining to Available Cash Generated	The following table details the quarterly distributions paid to common unitholders since our IPO in July 2012 (in millions, except per unit amounts):
	Date Declared	Date Paid		Common Units and equivalents (in millions)		Distribution per common unit and equivalent			Total Distribution (in millions)
	2012 Distributions:
	November 12, 2012	November 29, 2012		92		$	1.48		$	136.1
	Total distributions paid during 2012					$	1.48		$	136.1
	2013 Distributions:
	11-Feb-13	February 28, 2013		91.9		$	1.27		$	116.7
	13-May-13	May 30, 2013		92.2		$	1.23		113.4
	13-Aug-13	August 29, 2013		92.2		$	0.68		62.7
	11-Nov-13	November 27, 2013		92.2		$	0.31		28.6
	Total distributions paid during 2013					$	3.49		$	321.4
	2014 Distributions:
	February 7, 2014	February 28, 2014		92.7		$	0.41		$	38
	May 6, 2014	May 30, 2014		93		$	0.77		71.6
	August 5, 2014	August 29, 2014		93		$	0.53		49.3
	November 4, 2014	November 25, 2014		93.1		$	1		92.9
	Total distributions paid during 2014					$	2.71		$	251.8
Computation of Basic and Diluted Earnings Per Unit
		Year Ended December 31,
	(in millions, except unit and per-unit data)	2014			2013			2012
	Net income available to common unitholders (a)	$	241.6		$	231.1		$	126.9
	Less: income allocated to participating securities	(1.1		)	(0.6		)	—
	Net income attributable to unrestricted common units	$	240.5		$	230.5		$	126.9
	Weighted average unrestricted common units - basic	92,222,793			91,915,335			91,915,000
	Plus: dilutive potential common securities	37,252			—			—
	Weighted average unrestricted common units - diluted	92,260,045			91,915,335			91,915,000
	Basic earnings per unit	$	2.61		$	2.51		$	1.38
	Diluted earnings per unit	$	2.61		$	2.51		$	1.38
	(a) for 2012 calculations, net income available to common unitholders excludes earnings attributable to the period prior to our IPO date of July 31, 2012

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Assets and Liabilities Carried at Fair Value Measured on Recurring Basis	The following table provides the assets and liabilities carried at fair value measured on a recurring basis at December 31, 2014 and 2013:
		Balance at			Quoted prices in active markets			Significant other observable inputs			Unobservable inputs
	(in millions)	December 31, 2014			(Level 1)			(Level 2)			(Level 3)
	ASSETS
	Cash and cash equivalents	$	87.9		$	87.9		$	—		$	—
	Other current assets
	Derivative asset - current	1.7			—			1.7			—
		$	89.6		$	87.9		$	1.7		$	—
	LIABILITIES
	Accrued liabilities
	Derivative liability - current	$	4.1		$	—		$	4.1		$	—
	Other liabilities
	Derivative liability - long-term	0.4			—			0.4			—
		$	4.5		$	—		$	4.5		$	—
		Balance at			Quoted prices in active markets			Significant other observable inputs			Unobservable inputs
	(in millions)	December 31, 2013			(Level 1)			(Level 2)			(Level 3)
	ASSETS
	Cash and cash equivalents	$	85.8		$	85.8		$	—		$	—
		$	85.8		$	85.8		$	—		$	—
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	Changes in the fair value of the Company’s Level 3 contingent consideration arrangements during the year ended December 31, 2012 were due to updated financial performance estimates and are as follows:
		Margin						Net
	(in millions)	Support			Earnout			Impact
	Fair Value at December 31, 2011	$	20.2		$	(30.9	)	$	(10.7	)
	Change in fair value of remaining years	(20.2		)	(84.1		)	(104.3		)
	Settlement of contingent consideration agreements	—			115			115
	Fair Value at December 31, 2012	$	—		$	—		$	—
Fair Value of Secured Notes	The fair value of the 2020 Secured Notes disclosed below was determined based on quoted prices in active markets (Level 1).
		December 31, 2014						December 31, 2013
	(in millions)	Carrying Amount			Fair Value			Carrying Amount			Fair Value
	2020 Secured Notes	$	354.2		$	351.3		$	275		$	291.1

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Changes in Asset Retirement Obligations	The following table summarizes the changes in asset retirement obligations:
		Year Ended December 31,
	(in millions)	2014		2013		2012
	Asset retirement obligation balance at beginning of period	$	2.2	$	1.9	$	1.5
	Revisions of previous estimates	—		—		0.2
	Accretion expense	0.2		0.3		0.2
	Asset retirement obligation balance at end of period	$	2.4	$	2.2	$	1.9

EquityBased_Compensation_Table

Equity-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of LTIP Unit Activity	A summary of the restricted common unit activity is set forth below:
		Number of		Weighted			Weighted Average Term
		restricted common units		Average Grant			Until Maturity
		(in thousands)		Date Price			(years)
	Outstanding at December 31, 2012	6.1		$	25.69		3
	Awarded	321.9		27.02			3.5
	Cancelled	(3.5	)	28.28			—
	Vested	(17.9	)	26.38			—
	Nonvested at December 31, 2013	306.6		$	27.02		2.9
	Awarded	486.9		24.31			2
	Cancelled	(7.2	)	25.21			—
	Vested	(390.1	)	25.99			—
	Nonvested at December 31, 2014	396.2		$	24.73		1.3
NT Investor Plans Profit Interest Unit Activity	A summary of the NT Investor Plan's profit interest unit activity is set forth below:
		Number of NT Investor Profit Units		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term
		(in millions)				(years)
	Outstanding at December 31, 2012	19.5		1.96		8.1
	Vested	(19.5	)	1.96
	Outstanding at December 31, 2013	—		—		—
Assumptions Used to Estimate Weighted Average Fair Value as of Grant Date of Units Granted	The estimated weighted average fair value as of the grant date for NT Investor Plan profit interest units granted during the year ended December 31, 2012, was $0.88, based upon the following assumptions:
		2012
	Expected life (years)	6.5
	Expected volatility	55.50%
	Expected dividend yield	0.00%
	Risk-free interest rate	1.40%

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Changes to Benefit Obligation, Fair Value of Plan Assets and Funded Status of Cash Balance Plan and the Retiree Medical Plan	The changes to the benefit obligation, fair value of plan assets and funded status of the Cash Balance Plan and the Retiree Medical Plan (the “Plans”) for the years ended December 31, 2014, 2013 and 2012 were as follows:
				Cash Balance Plan												Retiree Medical Plan
				Year Ended December 31,												Year Ended December 31,
	(in millions)			2014				2013				2012				2014				2013				2012
	Change in benefit obligation:
		Benefit obligation at beginning of year		$	4.6			$	2.3			$	0.5			$	2.1			$	2.4			$	—
			Service cost	2.1				1.9				1.7				0.2				0.3				0.1
			Interest cost	0.3				0.2				0.1				0.1				0.1				0.1
			Actuarial loss (gain)	0.6				0.3				0.1				0.7				(0.6		)		0.8
			Plan amendments	—				—				—				—				—				1.4
			Benefits paid	(0.6		)		(0.1		)		(0.1		)		—				(0.1		)		—
		Benefit obligation at end of year		7				4.6				2.3				3.1				2.1				2.4
	Change in plan assets:
		Fair value of plan assets at beginning of year		4.6				2.1				0.1				—				—				—
			Employer contributions	0.2				2.5				2.1				—				0.1				—
			Return on plan assets	0.1				0.1				—				—				—				—
			Benefits paid	(0.6		)		(0.1		)		(0.1		)		—				(0.1		)		—
		Fair value of plan assets at end of year		4.3				4.6				2.1				—				—				—
	Reconciliation of funded status:
		Fair value of plan assets at end of year		4.3				4.6				2.1				—				—				—
		Benefit obligation at end of year		7				4.6				2.3				3.1				2.1				2.4
		Funded status at end of year		$	(2.7	)		$	—			$	(0.2	)		$	(3.1	)		$	(2.1	)		$	(2.4	)
Components of Net Period Benefit Cost and other Amounts Recognized in Equity	The components of net periodic benefit cost and other amounts recognized in equity related to the Plans for the years ended December 31, 2014, 2013 and 2012 were as follows:
			Cash Balance Plan												Retiree Medical Plan
			Year Ended December 31,												Year Ended December 31,
	(in millions)		2014				2013				2012				2014				2013				2012
	Components of net periodic benefit cost:
		Service cost	$	2.1			$	1.9			$	1.7			$	0.2			$	0.3			$	0.1
		Amortization of prior service cost	—				—				—				0.1				0.2				0.1
		Interest cost	0.3				0.2				0.1				0.1				0.1				0.1
		Expected return on plan assets	(0.2		)		(0.1		)		—				—				—				—
		Net periodic benefit cost	$	2.2			$	2			$	1.8			$	0.4			$	0.6			$	0.3
	Changes recognized in other comprehensive (income) loss:
		Prior service cost addition (amortization)	$	—			$	—			$	(0.1	)		$	(0.2	)		$	(0.2	)		$	1.3
		Actuarial (gain) loss	0.7				0.3				—				0.7				(0.6		)		0.8
		Experience loss	—				—				0.1				—				—				—
		Total changes recognized in other comprehensive (income) loss	$	0.7			$	0.3			$	—			$	0.5			$	(0.8	)		$	2.1
Anticipated Benefit Payments to Participants from Cash Balance Plan in Future Years	At December 31, 2014, anticipated benefit payments to participants from the Plans in future years are as follows:
	(in millions)	Cash Balance Plan				Retiree Medical Plan
	2015	$	0.3			$	0.1
	2016	0.4				0.1
	2017	0.5				0.1
	2018	0.6				0.1
	2019	0.8				0.1
	2020-2024	6.5				1
Benefit Obligation
Defined Benefit Plan Disclosure [Line Items]
Weighted Average Assumptions Used	The weighted average assumptions used to determine the Company’s benefit obligations are as follows:
		Cash Balance Plan						Retiree Medical Plan
		Year Ended December 31,						Year Ended December 31,
		2014		2013		2012		2014		2013		2012
	Discount rate	4.00%		5.00%		4.00%		4.00%		5.00%		4.00%
	Rate of compensation increase	3.00%		4.00%		4.00%		N/A		N/A		N/A
	Health care cost trend rate:
	Initial rate	N/A		N/A		N/A		7.50%		7.00%		7.50%
	Ultimate rate	N/A		N/A		N/A		5.00%		5.00%		5.00%
	Years to ultimate	N/A		N/A		N/A		5		4		5
Net Periodic Benefit Cost
Defined Benefit Plan Disclosure [Line Items]
Weighted Average Assumptions Used	The weighted average assumptions used to determine the net periodic benefit cost are as follows:
		Cash Balance Plan						Retiree Medical Plan
		Year Ended December 31,						Year Ended December 31,
		2014		2013		2012		2014		2013		2012
	Discount rate	5.00%		4.00%		4.75%		5.00%		4.00%		4.75%
	Expected long-term rate of return on plan assets	4.75%		4.25%		4.50%		N/A		N/A		N/A
	Rate of compensation increase	4.00%		4.00%		4.00%		N/A		N/A		N/A
	Heather care cost trend rate:
	Initial rate	N/A		N/A		N/A		7.00%		7.50%		7.50%
	Ultimate rate	N/A		N/A		N/A		5.00%		5.00%		5.00%
	Years to ultimate	N/A		N/A		N/A		4		5		5

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental cash flow information is as follows:
		Year Ended December 31,
	(in millions)	2014		2013		2012
	Net cash from operating activities included:
	Interest paid	$	22.5	$	26.7	$	32.9
	Income taxes paid	5		3.7		—
	Noncash investing and financing activities include:
	Capital expenditures included in accounts payable	$	2.9	$	10.2	$	1.2
	PP&E derecognized in sale leaseback	—		—		(4.7		)
	PP&E additions resulting from a capital lease	1.7		1.2		1

Leasing_Arrangements_Tables

Leasing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule of Future Minimum Lease Payments for Capital Leases	Future minimum commitments for operating lease obligations having an initial or remaining non-cancelable lease terms in excess of one year are as follows:
	(in millions)	Capital Leases			Operating Leases		Total Leases
	2015	$	1.2		$	22.7	$	23.9
	2016	1.2			23.4		$	24.6
	2017	1			22.7		$	23.7
	2018	0.9			22.2		$	23.1
	2019	0.9			21.8		$	22.7
	Thereafter	9.2			133		142.2
	Total	$	14.4		$	245.8	$	260.2
	Less: amount representing interest	$	(9.6	)	$	—	$	(9.6	)
	Present value of net minimum lease payments	$	4.8		$	245.8	$	250.6
Schedule of Future Minimum Rental Payments for Operating Leases	Future minimum commitments for operating lease obligations having an initial or remaining non-cancelable lease terms in excess of one year are as follows:
	(in millions)	Capital Leases			Operating Leases		Total Leases
	2015	$	1.2		$	22.7	$	23.9
	2016	1.2			23.4		$	24.6
	2017	1			22.7		$	23.7
	2018	0.9			22.2		$	23.1
	2019	0.9			21.8		$	22.7
	Thereafter	9.2			133		142.2
	Total	$	14.4		$	245.8	$	260.2
	Less: amount representing interest	$	(9.6	)	$	—	$	(9.6	)
	Present value of net minimum lease payments	$	4.8		$	245.8	$	250.6

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Operating Results for Operating Segments	Operating results for the Company’s operating segments are as follows:
	(in millions)
	Year ended December 31, 2014	Refining		Retail		Other			Total
	Revenues
	Customer	$	4,165.60	$	1,390.40	$	—		$	5,556.00
	Intersegment	932.1		—		—			932.1
	Segment revenues	5,097.70		1,390.40		—			6,488.10
	Elimination of intersegment revenues	—		—		(932.1		)	(932.1		)
	Total revenues	$	5,097.70	$	1,390.40	$	(932.1	)	$	5,556.00
	Income (loss) from operations	$	303.5	$	22.9	$	(51.1	)	$	275.3
	Income from equity method investment	$	2.2	$	—	$	—		$	2.2
	Depreciation and amortization	$	33.7	$	7.3	$	0.9		$	41.9
	Capital expenditures	$	35.4	$	8.8	$	0.6		$	44.8
	(in millions)
	Year ended December 31, 2013	Refining		Retail		Other			Total
	Revenues
	Customer	$	3,520.20	$	1,459.00	$	—		$	4,979.20
	Intersegment	1,015.80		—		—			1,015.80
	Segment revenues	4,536.00		1,459.00		—			5,995.00
	Elimination of intersegment revenues	—		—		(1,015.8		)	(1,015.8		)
	Total revenues	$	4,536.00	$	1,459.00	$	(1,015.8	)	$	4,979.20
	Income (loss) from operations	$	263.1	$	15.2	$	(32.2	)	$	246.1
	Income from equity method investment	$	10	$	—	$	—		$	10
	Depreciation and amortization	$	30.4	$	7.1	$	0.6		$	38.1
	Capital expenditures	$	88.7	$	7.7	$	0.2		$	96.6
	(in millions)
	Year ended December 31, 2012	Refining		Retail		Other			Total
	Revenues
	Customer	$	3,171.50	$	1,482.40	$	—		$	4,653.90
	Intersegment	1,041.10		—		—			1,041.10
	Segment revenues	4,212.60		1,482.40		—			5,695.00
	Elimination of intersegment revenues	—		—		(1,041.1		)	(1,041.1		)
	Total revenues	$	4,212.60	$	1,482.40	$	(1,041.1	)	$	4,653.90
	Income (loss) from operations	$	705.6	$	8.7	$	(145.0	)	$	569.3
	Income from equity method investment	$	12.3	$	—	$	—		$	12.3
	Depreciation and amortization	$	25.4	$	6.6	$	1.2		$	33.2
	Capital expenditures	$	24.2	$	4.6	$	2.1		$	30.9
Total Assets by Segment	Total assets by segment were as follows:
	(in millions)	Refining		Retail		Corporate/Other			Total
	At December 31, 2014	$	932.9	$	134	$	113.5		$	1,180.40
	At December 31, 2013	$	875.6	$	138.2	$	104		$	1,117.80

Reorganization_and_Related_Cos1

Reorganization and Related Costs (Tables)	12 Months Ended
	Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Schedule of Reorganization Reserve
	(in millions)	For the year ended December 31, 2014
	Reorganization and related costs incurred during period	$	12.9
	Less: non-cash equity based awards with accelerated vesting	(4.8		)
	Cash payments made to severed employees	(7.3		)
	Ending liability for cash portion of reorganization costs	$	0.8

Supplementary_Quarterly_Financ1

Supplementary Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information
	(in millions, except per unit data)		First Quarter		Second Quarter		Third Quarter		Fourth Quarter		Total
	2014
		Revenue	$	1,346.30	$	1,602.50	$	1,547.40	$	1,059.80	$	5,556.00
		Operating income	77.8		65.6		104.8		27.1		275.3
		Net income	71.5		57.9		96.2		16		241.6
		Earnings per common unit - basic	$	0.77	$	0.62	$	1.04	$	0.17	$	2.61
		Earnings per common unit - diluted	$	0.77	$	0.62	$	1.04	$	0.17	$	2.61
	2013
		Revenue	$	1,115.00	$	1,131.20	$	1,440.90	$	1,292.10	$	4,979.20
		Operating income	132.2		52.6		27.5		33.8		246.1
		Net income	119.4		63.9		27.2		20.6		231.1
		Earnings per common unit - basic and diluted	$	1.3	$	0.7	$	0.3	$	0.22	$	2.51

Description_of_the_Business_an1

Description of the Business and Basis of Presentation - Additional Information (Details) (USD $)	0 Months Ended	12 Months Ended		0 Months Ended	1 Months Ended
	Nov. 12, 2013	Dec. 31, 2013	Dec. 31, 2014	Dec. 01, 2010	Dec. 01, 2010	Dec. 31, 2012
			bbl
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Membership Interest						100.00%
Proceeds from transaction	$0	$0
Number of stores			254
Retail
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of stores			165
Western Refining, Inc.
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Business acquisition, price	775,000,000
Investment Owned, Balance, Shares	35,622,500
Western Refining, Inc. | Northern Tier Energy GP LLC
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Sale of Stock, Percentage of Ownership after Transaction	100.00%
Minnesota Pipe Line Company
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Membership Interest			17.00%
Preferred interest by parent			100.00%
Crude oil pipeline capacity (in barrels)			455,000
Mpl Investments Inc
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Membership Interest			17.00%
St Paul Park Refining Company
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of barrels of refinery crude oil capacity per stream day			97,800
Super America Franchising Company | Franchised
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of stores			89
Northern Tier Energy LLC
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Membership Interest			100.00%
Marathon
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Business acquisition, price				$608,000,000	$608,000,000
Number of stores			135

Summary_of_Principal_Accountin2

Summary of Principal Accounting Policies - Additional Information (Details) (USD $)	5 Months Ended	12 Months Ended			0 Months Ended	1 Months Ended	3 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 25, 2012	Jul. 31, 2012	Sep. 30, 2012	Sep. 30, 2013
		Segment
		Store
Summary Of Significant Accounting Policies [Line Items]
Investment in MPLI at cost		$6.80	$6.80
Reportable operating segments		2
Retail operated convenience stores		254
Required Frequency of the maintenance, minimum		2 years
Required Frequency of the maintenance, maximum		6 years
Excise taxes		396.4	316.4	300.1
Advertising expense		2.3	2	1.5
Allowance for doubtful debts		0.2	0.2
Accumulated unrecognized costs related to defined benefit plan		3.2	2
Other comprehensive gain/(loss)	-2.1	-1.2	0.5	-2.1
Derivative, Gain (Loss) on Derivative, Net		9.6	23.5	-271.4
Income (Loss) from Equity Method Investments		2.2	10	12.3
Cost of Sales
Summary Of Significant Accounting Policies [Line Items]
Derivative, Gain (Loss) on Derivative, Net		9.6	7.4	-1.7
Customer Concentration Risk | Sales Revenue, Net
Summary Of Significant Accounting Policies [Line Items]
Number of major customers		0
Maximum
Summary Of Significant Accounting Policies [Line Items]
Highly liquid investments maturities periods to qualify as cash equivalents		3 months
Retail
Summary Of Significant Accounting Policies [Line Items]
Retail operated convenience stores		165
Income (Loss) from Equity Method Investments		$0	$0	$0
Northern Tier Holdings | Common Units
Summary Of Significant Accounting Policies [Line Items]
Units issued in exchange for membership interests						54,844,500		54,844,500
Northern Tier Holdings | PIK units
Summary Of Significant Accounting Policies [Line Items]
Units issued in exchange for membership interests						18,383,000		18,383,000
IPO
Summary Of Significant Accounting Policies [Line Items]
Limited partnership units issued to the public					18,687,500	18,687,500	18,687,500

Initial_Public_Offering_of_Nor1

Initial Public Offering of Northern Tier Energy LP - Additional Information (Details) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended	12 Months Ended			1 Months Ended
In Millions, except Share data, unless otherwise specified	Jul. 25, 2012	Aug. 31, 2012	Sep. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 31, 2012	Sep. 30, 2013
Equity and Equity Units Offering Disclosure [Line Items]
Common stock value per share	$14
Shares issued to the underwriters on exercise of over-allotment option							2,437,500
Contribution from Member				$0	$0	$230.40
Distribution made to equity holders				251.8	321.4	300.2
Payment to J. Aron & Company related to deferred payment obligations from the early extinguishment of derivatives		-92
Loss on extinguishment of debt				0	0	50
Redemption percentage of 2017 Secured Notes	103.00%
Percentage of limited partner interest issued to the public			20.30%
ACON Refining Partners LLC and TPG Refining LP
Equity and Equity Units Offering Disclosure [Line Items]
Distribution made to equity holders	32
Northern Tier Holdings
Equity and Equity Units Offering Disclosure [Line Items]
Proceeds from IPO used to redeem preferred interest in Northern Tier Holdings					92
NTE LLC
Equity and Equity Units Offering Disclosure [Line Items]
Payment of principal and interest on redemption of 2017 Secured Notes	31
IPO
Equity and Equity Units Offering Disclosure [Line Items]
Limited partnership units issued to the public	18,687,500		18,687,500				18,687,500
Contribution from Member	245
Cash on hand	56
Payment to J. Aron & Company related to deferred payment obligations from the early extinguishment of derivatives	92
Loss on extinguishment of debt	29
Offering costs	15
IPO | Marathon
Equity and Equity Units Offering Disclosure [Line Items]
Proceeds from IPO used to redeem preferred interest in Northern Tier Holdings	92
Settlement payment for contingent consideration agreement	40
IPO | Northern Tier Holdings
Equity and Equity Units Offering Disclosure [Line Items]
Distribution made to equity holders	$124
Common Units
Equity and Equity Units Offering Disclosure [Line Items]
Number of units priced	16,250,000
Common Units | Northern Tier Holdings
Equity and Equity Units Offering Disclosure [Line Items]
Units issued in exchange for membership interests							54,844,500	54,844,500
PIK units | Northern Tier Holdings
Equity and Equity Units Offering Disclosure [Line Items]
Units issued in exchange for membership interests							18,383,000	18,383,000

Related_Party_Transactions_Add

Related Party Transactions - Additional Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction		$0
Incentive fee description	Quarterly management fees equal to 1% of the Companybs bAdjusted EBITDAb (as defined in the agreement)
Due from affiliate, current	5,100,000
Due to affiliate, current	2,100,000
Quarterly management fee percentage of Adjusted EBITDA (as defined in the agreement)	1.00%
Minimum annual management fee payable to sponsors	2,000,000
Management fees, amount			3,100,000
Success fee	7,500,000
Crude Oil [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	6,300,000
Refined Product [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	19,000,000
RINs and Rail Car Lease [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	100,000
shared service [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	1,100,000
Pipeline costs [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	$12,600,000

Marathon_Acquisition_Additiona

Marathon Acquisition - Additional Information (Details) (USD $)	12 Months Ended			0 Months Ended	1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 01, 2010	Dec. 01, 2010	Jul. 31, 2012
Business Acquisition [Line Items]
Non-cash contingent consideration loss (income)	$0	$0	($104,300,000)
Marathon
Business Acquisition [Line Items]
Business acquisition, price				608,000,000	608,000,000
Maximum amount NTE LLC could have been required to pay under earn-out agreement				125,000,000
Record liability						85,000,000
Marathon | Margin-support consideration which is a component of the contingent consideration
Business Acquisition [Line Items]
Maximum amount NTE LLC could have received under margin support agreement				$60,000,000	$60,000,000

Income_Taxes_Income_Tax_Provis

Income Taxes Income Tax Provision (Details) (USD $)	0 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Aug. 01, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Current tax expense		$4.50	$3.30	$0
Deferred income taxes	8	2.6	0.9	9.8
Income tax provision		$7.10	$4.20	$9.80

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Details) (USD $)	0 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Aug. 01, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Net deferred tax charge	$8	$2.60	$0.90	$9.80
Current deferred tax asset	2.2
Non-current deferred tax liability	10.2
Effective tax rate		2.90%	1.80%	4.70%
Combined federal income tax rate and state income tax rate, net of federal benefit		40.40%
Tax loss carryforwards			2.1
Deferred Tax Assets, Operating Loss Carryforwards			$0

Income_Taxes_Reconciliation_of

Income Taxes Reconciliation of Effective Income Tax Rate (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%
Federal statutory rate applied to income before taxes	$87	$82.40	$72.60
Taxes on earnings attributable to flow-through entities	-81	-78.6	-71.6
State and local income taxes, net of federal tax effects	1	0.9	0
Initial charge upon NTRH's election to be treated as a corporation	0	0	8
Work opportunity tax credit	-0.3	-0.6	0
Other, net	0.4	0.1	0.8
Income tax provision	$7.10	$4.20	$9.80

Income_Taxes_Deferred_Tax_Asse

Income Taxes Deferred Tax Assets Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Deferred tax assets:
Lease financing obligations	$2.40	$2.60
Customer loyalty accrual	0.9	0.9
Other	0.8	1.1
Deferred tax assets	4.1	4.6
Deferred tax liabilities:
Accelerated depreciation	-5.4	-3.4
Intangible assets	-11.8	-11.7
Other	-0.2	-0.2
Deferred tax liabilities	-17.4	-15.3
Total deferred taxes, net	($13.30)	($10.70)

Inventories_Details

Inventories (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Crude oil and refinery feedstocks	$137.50	$29.40
Refined products	150	106.7
Merchandise	22.3	22.6
Supplies and sundry items	15.9	14.8
Inventory, Net Before Adjustments	325.7	173.5
Lower of cost or market inventory reserve	-73.6	0
Total	$252.10	$173.50

Inventories_Additional_Informa

Inventories - Additional Information (Details) (USD $)	0 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	bbl
Inventory Disclosure [Abstract]
Percentage of LIFO Inventory		88.00%	78.00%
BARRELS OF CRUDE OIL PURCHASED	1,200,000
Lower of Cost or Market Inventory Adjustment		$73.60	$0
LIFO liquidation, effect in cost of sales			$1	$0

Equity_Method_Investment_Addit

Equity Method Investment - Additional Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Method Investments and Joint Ventures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Common interest in Minnesota Pipe Line	17.00%
Carrying value of equity method investment	$80.70	$86.20
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	6.2	6.4
Distribution received	7.5	11.1	14.5
Equity Income from Minnesota Pipe Line	$2.20	$10	$12.30

Equity_Method_Investment_Summa

Equity Method Investment Summarized Financial Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Income from equity method investment	$2.20	$10	$12.30
Minnesota Pipe Line Company
Schedule of Equity Method Investments [Line Items]
Revenues	184.7	161.9	153.6
Operating costs and expenses	141.3	74.5	52.7
Income from operations	43.4	68.2	82.1
Net income	22.8	68.2	82.1
Income from equity method investment	13.1	58.6	72.4
Current assets	9.6	26.1
Noncurrent assets	450.7	462.9
Total assets	460.3	489
Current liabilities	21.9	19.8
Noncurrent liabilities	0	0
Total liabilities	21.9	19.8
Members capital	$438.40	$469.20

Property_Plant_and_Equipment_D

Property, Plant and Equipment (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Gross	$584.90	$544.60
Less: Accumulated depreciation	-139.1	-98.4
Property, plant and equipment, net	445.8	446.2
Land
Property, Plant and Equipment [Line Items]
Gross	9	9
Retail stores and equipment
Property, Plant and Equipment [Line Items]
Gross	65.7	54.9
Retail stores and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	2 years
Retail stores and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	22 years
Refinery and equipment
Property, Plant and Equipment [Line Items]
Gross	444.6	403.5
Refinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years
Refinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	24 years
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	25 years
Gross	10.2	8.9
Software
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years
Gross	18.8	18.6
Vehicles
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	5 years
Gross	4.7	4.7
Other equipment
Property, Plant and Equipment [Line Items]
Gross	9.1	8.5
Other equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	2 years
Other equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	7 years
Precious Metals
Property, Plant and Equipment [Line Items]
Gross	10.2	10.2
Asset under Construction
Property, Plant and Equipment [Line Items]
Gross	$12.60	$26.30

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Gross assets acquired under capital leases	$10.80	$8.60
Accumulated depreciation	1.7	1.2
Capitalized Software
Property, Plant and Equipment [Line Items]
Depreciation expense	$3.70	$3.70	$3.20

Intangible_Assets_Additional_I

Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 01, 2010
Intangible assets (reduction to)	$33.80	$33.80
Franchise rights acquisition	12.4
Trademarks acquisition	21.4
Reduction to other liabilities	-27	-17.8
Income tax benefit	-7.1	-4.2	-9.8
Initial valuation of intangible assets | Restatement adjustment
Intangible assets (reduction to)		-1.6		-1.6
Reduction to other liabilities		0.6
Intangibles impairment		1.6
Income tax benefit		$0.60

Derivatives_Notional_Amounts_D

Derivatives Notional Amounts (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	bbl	bbl
Crude Oil and Refined Product futures and swaps
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume	-124,000	0
Natural gas swaps
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume	617,000	0

Derivatives_Recognized_Gains_a

Derivatives Recognized Gains and Losses on Derivative (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on the change in fair value of outstanding derivatives	($2.80)	$41.60	$68
Settled derivative gains (losses)	12.4	-18.1	-339.4
Total recognized gain (loss)	9.6	23.5	-271.4
Gain (Loss) on Derivative Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total recognized gain (loss)	0	16.1	-269.7
Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Total recognized gain (loss)	$9.60	$7.40	($1.70)

Fair_Value_Amounts_of_Outstand

Fair Value Amounts of Outstanding Derivative Instruments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivatives, Fair Value [Line Items]
Other current assets	$1.70
Accrued liabilities	-4.1
Derivative Liability, Noncurrent	-0.4
Net asset (liability) position	-2.8	0
Commodity Swaps And Futures
Derivatives, Fair Value [Line Items]
Other current assets	1.7	0
Accrued liabilities	-4.1	0
Derivative Liability, Noncurrent	($0.40)	$0

Derivatives_Additional_Informa

Derivatives - Additional Information (Details) (USD $)	1 Months Ended	6 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Aug. 31, 2012	Jun. 30, 2013	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2013
Derivative [Line Items]
Loss recognized		$136.80
Payment related to early settlement of derivative losses	92
Interest rate on deferred payment derivative losses			7.10%
Long-term liabilities			27		17.8
Deferred Loss on Early Extinguishment of Debt
Derivative [Line Items]
Interest expense			0.7	2.5
Current liabilities			0.9		28.9
Long-term liabilities					$0.90

Derivatives_Derivative_Maturit

Derivatives Derivative Maturities (Details)	12 Months Ended
	Dec. 31, 2014
	Boe
Crude Oil and Refined Product futures and swaps
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume	-124,000
Deferred Loss on Early Extinguishment of Debt
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume	419,000
Crude Oil and Refined Product futures and swaps, Year Two
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume	0
Deferred Gain (Loss) on Early Extinguishment of Debt, Year Two
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume	198,000

Debt_Additional_Information_De

Debt - Additional Information (Details) (USD $)	0 Months Ended		1 Months Ended	12 Months Ended			0 Months Ended
	Sep. 27, 2014	Dec. 12, 2013	Jul. 17, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 12, 2013	Sep. 29, 2014	Nov. 08, 2012
Debt Instrument [Line Items]
Principal amount of debt redeemed				$0	$0	$50,000,000
redemption period		30 days
Debt principal amount				354,200,000	275,000,000
Borrowings from senior secured notes				79,200,000	0	275,000,000
premium percentage								105.75%
Debt Instrument, Unamortized Premium								4,200,000
Commitment amount	500,000,000
Credit facility, covenant terms			The Amended ABL Facility includes a springing financial covenant to provide that, if the amount available under the revolving credit facility is less than the greater of (i)B 12.5% (changed from 15%) of the lesser of (x)B the $300 million commitment amount and (y)B the then-applicable borrowing base and (ii)B $22.5 million, the Company must comply with a minimum Fixed Charge Coverage Ratio (as defined in the Amended ABL Facility) of at least 1.0 to 1.0.
Debt, interest rate description				(a)B an alternative base rate, plus an applicable margin (ranging between 1.00% and 1.50%) or (b)B a LIBOR rate plus applicable margin (ranging between 2.00% and 2.50%). The alternate base rate is the greater of (a)B the prime rate, (b)B the Federal Funds Effective rate plus 50 basis points, or (c)B the one-month LIBOR rate plus 100 basis points and a spread of up to 225 basis points based upon percentage utilization of this facility.
Revolving credit facility, borrowing capacity				308,300,000
Availability under the revolving credit facility				296,200,000
Outstanding letter of credit				12,100,000
Credit facility outstanding				0	0
Loss on early extinguishment of debt				0	0	50,000,000
Minimum
Debt Instrument [Line Items]
Annual commitment fee	0.25%
Letter of Credit, percentage fee	1.50%
Maximum
Debt Instrument [Line Items]
Annual commitment fee	0.38%
Letter of Credit, percentage fee	2.00%
Base Rate Loans [Member] | Minimum
Debt Instrument [Line Items]
Variable rate	0.50%
Base Rate Loans [Member] | Maximum
Debt Instrument [Line Items]
Variable rate	1.00%
Libor Indexed Loans [Member] | Minimum
Debt Instrument [Line Items]
Variable rate	1.50%
Libor Indexed Loans [Member] | Maximum
Debt Instrument [Line Items]
Variable rate	2.00%
Revolving Credit Facility
Debt Instrument [Line Items]
Maturity date of revolving credit facility				29-Sep-19
Asset-based credit facility [Member]
Debt Instrument [Line Items]
Payments of Debt Issuance Costs				3,000,000
Secured Notes 2017 Issue
Debt Instrument [Line Items]
Debt instrument, redemption price						103.00%
Write off of Deferred Debt Issuance Cost						10,500,000
Gains (Losses) on Extinguishment of Debt, before Write off of Deferred Debt Issuance Cost						39,500,000
Debt Instrument Remaining Outstanding Principal Amount						3,000,000
Debt interest rate						10.50%
Secured Notes 2017 Issue | IPO
Debt Instrument [Line Items]
Principal amount of debt redeemed						29,000,000
Debt instrument, redemption price						103.00%
Secured Notes 2017 Issue | Concurrent Senior Notes 2020 Issued
Debt Instrument [Line Items]
Principal amount of debt redeemed						258,000,000
Debt instrument, redemption price						114.90%
Secured Notes 2020 Issue
Debt Instrument [Line Items]
Debt interest rate									7.13%
Repurchase offer, period							30 days
Repurchase offer, percent of principal							101.00%
Borrowings from senior secured notes				75,000,000
Payments of Debt Issuance Costs				$2,500,000

Equity_Additional_Information_

Equity - Additional Information (Details) (USD $)

0 Months Ended

5 Months Ended

7 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

3 Months Ended

Nov. 05, 2014

Nov. 12, 2013

Dec. 31, 2012

Jul. 31, 2012

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Feb. 06, 2015

Jul. 25, 2012

Jul. 31, 2012

Sep. 30, 2012

Mar. 31, 2015

Sep. 30, 2013

Limited Partners' Capital Account [Line Items]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

3 years

Common units

91,915,000

92,712,744

92,100,363

91,915,000

Proceeds from transaction

$0

$0

Number of days after the end of the quarter to make cash distributions to units holders

60 days

Quarterly distribution declared to common unitholders

$2.71

$3.49

$1.48

Distribution declaration date

4-Nov-14

Distribution payable date

25-Nov-14

Distributions

136,100,000

164,100,000

251,800,000

321,400,000

Subsequent Event

Limited Partners' Capital Account [Line Items]

Quarterly distribution declared to common unitholders

$0.49

Distribution declaration date

6-Feb-15

Distribution date of record

17-Feb-15

Distribution payable date

27-Feb-15

Distribution Made to Limited Partner, Cash Distributions Declared

45,600,000

Western Refining, Inc.

Limited Partners' Capital Account [Line Items]

Business acquisition, price

775,000,000

Common units owned

35,622,500

Western Refining, Inc. | Northern Tier Energy GP LLC

Limited Partners' Capital Account [Line Items]

Sale of Stock, Percentage of Ownership after Transaction

100.00%

Western Refining, Inc. | Limited Partner [Member]

Limited Partners' Capital Account [Line Items]

Sale of Stock, Percentage of Ownership after Transaction

38.70%

IPO

Limited Partners' Capital Account [Line Items]

Limited partnership units issued to the public

18,687,500

18,687,500

18,687,500

Common Units | Secondary Public Offering

Limited Partners' Capital Account [Line Items]

Number of secondary public offerings

3

Parent's equity units in registrant sold through public offerings

37,605,000

Formation and offering costs

1,500,000

Formation Costs Not Deferred

3,100,000

Northern Tier Holdings

Limited Partners' Capital Account [Line Items]

Distributions

124,200,000

Distributions used to redeem interest

92,000,000

Northern Tier Holdings | Common Units

Limited Partners' Capital Account [Line Items]

Units issued in exchange for membership interests

54,844,500

54,844,500

54,844,500

Northern Tier Holdings | PIK units

Limited Partners' Capital Account [Line Items]

Units issued in exchange for membership interests

18,383,000

18,383,000

18,383,000

Northern Tier Energy LLC

Limited Partners' Capital Account [Line Items]

Distributions

$40,000,000

Phantom Share Units (PSUs) [Member] | Subsequent Event

Limited Partners' Capital Account [Line Items]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

3 years

Distributions_Paid_During_or_P

Distributions Paid During or Pertaining to Available Cash Generated (Details) (USD $)	0 Months Ended	5 Months Ended	7 Months Ended	12 Months Ended			0 Months Ended
In Millions, except Share data, unless otherwise specified	Nov. 05, 2014	Dec. 31, 2012	Jul. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 06, 2014	6-May-14	Feb. 07, 2014	Nov. 27, 2013	Aug. 29, 2013	30-May-13	Feb. 28, 2013	Nov. 29, 2012	Nov. 04, 2014	Aug. 05, 2014
Distribution Made to Limited Partner [Line Items]
Date Declared	4-Nov-14
Date Paid	25-Nov-14
Common units			91,915,000	92,712,744	92,100,363
Distributions per common unit (in dollars per share)				$2.71	$3.49	$1.48
Total Distribution		$136.10	$164.10	$251.80	$321.40
Cash Distribution
Distribution Made to Limited Partner [Line Items]
Date Declared							5-Aug-14	6-May-14	7-Feb-14	11-Nov-13	13-Aug-13	13-May-13	11-Feb-13	12-Nov-12
Date Paid							29-Aug-14	30-May-14	28-Feb-14	27-Nov-13	29-Aug-13	30-May-13	28-Feb-13	29-Nov-12
Common units								93,000,000	92,700,000	92,200,000	92,200,000	92,200,000	91,900,000	92,000,000	93,100,000	93,000,000
Distributions per common unit (in dollars per share)	1			$2.71	$3.49	$1.48	$0.53	$0.77	$0.41	$0.31	$0.68	$1.23	$1.27	$1.48
Total Distribution	92.9			$251.80	$321.40	$136.10	$49.30	$71.60	$38	$28.60	$62.70	$113.40	$116.70	$136.10

Computation_of_Basic_and_Dilut

Computation of Basic and Diluted Earnings Per Unit (Details) (USD $)	3 Months Ended								5 Months Ended	7 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jul. 31, 2012	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Equity [Abstract]
Net income available to common unitholders	$16	$96.20	$57.90	$71.50	$20.60	$27.20	$63.90	$119.40	$126.90	$70.70	$241.60	[1]	$231.10	[1]	$197.60
Less: income allocated to participating securities											-1.1		-0.6
Net Income available to common unitholders											$240.50		$230.50		$126.90
Weighted Average Number of Shares Outstanding, Basic											92,222,793		91,915,335		91,915,000
Weighted Average Number Diluted Shares Outstanding Adjustment											37,252		0		0
Weighted Average Number of Shares Outstanding, Diluted											92,260,045		91,915,335		91,915,000
Earnings per unit, Basic (in dollars per share)	$0.17	$1.04	$0.62	$0.77							$2.61		$2.51		$1.38
Earnings per unit, Diluted (in dollars per share)	$0.17	$1.04	$0.62	$0.77							$2.61		$2.51		$1.38
[1]	(a) for 2012 calculations, net income available to common unitholders excludes earnings attributable to the period prior to our IPO date of July 31, 2012

Assets_and_Liabilities_Carried

Assets and Liabilities Carried at Fair Value Measured on Recurring Basis (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
ASSETS
Cash and cash equivalents	$87.90	$85.80
Other current assets
Derivative asset - current	1.7
Assets, Fair Value Disclosure, Recurring	89.6	85.8
LIABILITIES
Derivative liability - current	4.1
Derivative Liability, Noncurrent	0.4
Liabilities, Fair Value Disclosure, Recurring	4.5
Quoted prices in active markets (Level 1)
ASSETS
Cash and cash equivalents	87.9	85.8
Other current assets
Derivative asset - current	0
Assets, Fair Value Disclosure, Recurring	87.9	85.8
LIABILITIES
Derivative liability - current	0
Derivative Liability, Noncurrent	0
Liabilities, Fair Value Disclosure, Recurring	0
Significant other observable inputs (Level 2)
ASSETS
Cash and cash equivalents	0	0
Other current assets
Derivative asset - current	1.7
Assets, Fair Value Disclosure, Recurring	1.7	0
LIABILITIES
Derivative liability - current	4.1
Derivative Liability, Noncurrent	0.4
Liabilities, Fair Value Disclosure, Recurring	4.5
Unobservable inputs (Level 3)
ASSETS
Cash and cash equivalents	0	0
Other current assets
Derivative asset - current	0
Assets, Fair Value Disclosure, Recurring	0	0
LIABILITIES
Derivative liability - current	0
Derivative Liability, Noncurrent	0
Liabilities, Fair Value Disclosure, Recurring	$0

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Details) (USD $)	3 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value Disclosures [Abstract]
Margin support and earn-out agreements cash payment	$40,000,000
Margin support and earn-out agreements settled in preferred interest of parent	45,000,000
Forgiveness of margin support receivable	30,000,000
Contingent consideration loss		0	0	104,300,000
Fair value adjustment to assets		$0

Fair_Value_Measurements_Change

Fair Value Measurements Changes in Fair Value of Level 3 Contingent Consideration Arrangement (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Beginning Balance	($10.70)
Change in fair value of remaining years	-104.3
Settlement of contingent consideration agreements	115
Fair Value Ending Balance	0
Margin Support
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Beginning Balance	20.2
Change in fair value of remaining years	-20.2
Settlement of contingent consideration agreements	0
Fair Value Ending Balance	0
Earnout
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Beginning Balance	-30.9
Change in fair value of remaining years	-84.1
Settlement of contingent consideration agreements	115
Fair Value Ending Balance	$0

Fair_Value_of_Secured_Notes_De

Fair Value of Secured Notes (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Notes, Carrying Amount	$354.20	$275
Secured Notes 2020 Issue
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Notes, Carrying Amount	354.2	275
Secured Notes, Fair Value	$351.30	$291.10

Changes_in_Asset_Retirement_Ob

Changes in Asset Retirement Obligations (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation balance at beginning of period	$2.20	$1.90	$1.50
Revisions of previous estimates	0	0	0.2
Accretion expense	0.2	0.3	0.2
Asset retirement obligation balance at end of period	$2.40	$2.20	$1.90

EquityBased_Compensation_Addit

Equity-Based Compensation - Additional Information (Details) (USD $)	12 Months Ended			2 Months Ended	3 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 26, 2015	Mar. 31, 2015	Jan. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	$14	$7.10	$0.90
Restricted stock units outstanding	700,000
Vesting period	3 years
Common stock issued	92,712,744	92,100,363
LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common units reserved for issuance	8,100,000
Total unrecognized compensation cost	12.1	6.1
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding	396,200	306,600	6,100
days to pay distributions to restricted unit holders	30 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	486,900	321,900
Restricted Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected forfeiture rate	30.00%
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding	337,700	0
Dividends Payable	0.8
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	351,500
Phantom Share Units (PSUs) | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				700,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested				15.1
Vesting period					3 years
Phantom Share Units (PSUs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected forfeiture rate	5.00%
Phantom Share Units (PSUs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected forfeiture rate	20.00%
NT Investor Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common units reserved for issuance	29,000,000
Minimum percentage of the grant date equity fair value that the awards shall be priced at	100.00%
Vesting period	5 years
Profit interest expire period (Years)	10 years
Common stock issued						10,700,000
Equity based compensation recognized due to accelerated vesting event		5.3
Weighted average fair value of units granted			$0.88
Equity-based compensation expense		$5.30	$0.90

Summary_of_Award_Activity_Deta

Summary of Award Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of LTIP units
Number of LTIP units, outstanding ending balance	700,000
Restricted Stock
Number of LTIP units
Number of LTIP units, outstanding beginning balance	306,600	6,100
Number of LTIP units, Awarded	486,900	321,900
Number of LTIP units, Cancelled	-7,200	-3,500
Number of LTIP units, Vested	-390,100	-17,900
Number of LTIP units, outstanding ending balance	396,200	306,600	6,100
Weighted Average Grant Date Price
Weighted Average Grant Date Price outstanding (in dollars per share)	$27.02	$25.69
Weighted Average Grant Date Price awarded (in dollars per share)	$24.31	$27.02
Weighted Average Grant Date Price Cancelled (in dollars per share)	$25.21	$28.28
Weighted Average Grant Date Price Vested (in dollars per share)	$25.99	$26.38
Weighted Average Grant Date Price outstanding (in dollars per share)	$24.73	$27.02	$25.69
Weighted Average Term Until Maturity
Weighted Average Term Until Maturity Awarded	2 years	3 years 6 months
Weighted Average Term Until Maturity	1 year 3 months 18 days	2 years 10 months 24 days	3 years
Phantom Share Units (PSUs)
Number of LTIP units
Number of LTIP units, outstanding beginning balance	0
Number of LTIP units, Awarded	351,500
Number of LTIP units, Cancelled	-12,900
Number of LTIP units, Vested	-900
Number of LTIP units, outstanding ending balance	337,700
Weighted Average Grant Date Price
Weighted Average Grant Date Price outstanding (in dollars per share)	$0
Weighted Average Grant Date Price awarded (in dollars per share)	$26.99
Weighted Average Grant Date Price Cancelled (in dollars per share)	$27.01
Weighted Average Grant Date Price Vested (in dollars per share)	$27.01
Weighted Average Grant Date Price outstanding (in dollars per share)	$26.99
Weighted Average Term Until Maturity
Weighted Average Term Until Maturity Awarded	2 years 8 months 12 days
Weighted Average Term Until Maturity Cancelled	2 years 3 months 18 days
Weighted Average Term Until Maturity	2 years

EquityBased_Compensation_NT_In

Equity-Based Compensation NT Investor Plans Profit Interest Unit Activity (Details) (Investor Plan [Member], USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Investor Plan [Member]
Number of NT Investor Profit Units
Number of units outstanding at beginning of period	19.5
Number of units, vested	-19.5
Number of units outstanding at end of period	0	19.5
Weighted Average Exercise Price
Weighted average exercise price outstanding at beginning of period (in dollars per share)	$1.96
Weighted average exercise price, vested (in dollars per share)	$1.96
Weighted average exercise price outstanding at end of period (in dollars per share)	$0	$1.96
Weighted Average Remaining Contractual Term		8 years 1 month 6 days

EquityBased_Compensation_Assum

Equity-Based Compensation Assumptions Used to Estimate Weighted Average Fair Value as of Grant Date of Units Granted (Details) (Investor Plan [Member])	12 Months Ended
	Dec. 31, 2012
Investor Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (years)	6 years 6 months
Expected volatility	55.50%
Expected dividend yield	0.00%
Risk-free interest rate	1.40%

Employee_Benefit_Plans_Additio

Employee Benefit Plans - Additional Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Number Of Plans	2
Funded status at end of year	($5.80)	($2.10)
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	5.1
Defined Contribution Plans Non-Matching Contribution Percentage Range
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employers contribution	100.00%
Defined contribution plans, participant's contribution	6.00%
Defined contribution plans, non-elective fixed annual contribution	3.00%
Defined Contribution Plans Matching Contribution Percentage Range
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plans, non-elective fixed annual contribution	3.50%
Retirement And Savings Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contribution to defined benefit plan	7.1	6.1	3.7
Cash Balance Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employers contribution	5.00%
Employer contribution to defined benefit plan	0.2	2.5	2.1
US treasury bond maturity term used to determine employer contributions	30 years
Participants full vested period	3 years
Funded status at end of year	-2.7	0	-0.2
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	0.3
Retiree Medical Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contribution to defined benefit plan	0	0.1	0
Participants full vested period	10 years
Funded status at end of year	-3.1	-2.1	-2.4
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	$0.10
Retiree Medical Plan | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Health care benefit plan for employees, age limit	55 years
Retiree Medical Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Health care benefit plan for employees, age limit	65 years

Employee_Benefit_Plans_Changes

Employee Benefit Plans Changes to Benefit Obligation, Fair Value of Plan Assets and Funded Status of Cash Balance Plan (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of funded status:
Funded status at end of year	($5.80)	($2.10)
Cash Balance Plan
Change in benefit obligation:
Benefit obligation at beginning of year	4.6	2.3	0.5
Service cost	2.1	1.9	1.7
Interest cost	0.3	0.2	0.1
Actuarial loss (gain)	0.6	0.3	0.1
Plan amendments	0	0	0
Benefits paid	-0.6	-0.1	-0.1
Benefit obligation at end of year	7	4.6	2.3
Change in plan assets:
Fair value of plan assets at beginning of year	4.6	2.1	0.1
Employer contributions	0.2	2.5	2.1
Return on plan assets	0.1	0.1	0
Benefits paid	-0.6	-0.1	-0.1
Fair value of plan assets at end of year	4.3	4.6	2.1
Reconciliation of funded status:
Fair value of plan assets at end of year	4.3	4.6	2.1
Benefit obligation at end of year	7	4.6	2.3
Funded status at end of year	-2.7	0	-0.2
Retiree Medical Plan
Change in benefit obligation:
Benefit obligation at beginning of year	2.1	2.4	0
Service cost	0.2	0.3	0.1
Interest cost	0.1	0.1	0.1
Actuarial loss (gain)	0.7	-0.6	0.8
Plan amendments	0	0	1.4
Benefits paid	0	-0.1	0
Benefit obligation at end of year	3.1	2.1	2.4
Change in plan assets:
Fair value of plan assets at beginning of year	0	0	0
Employer contributions	0	0.1	0
Return on plan assets	0	0	0
Benefits paid	0	-0.1	0
Fair value of plan assets at end of year	0	0	0
Reconciliation of funded status:
Fair value of plan assets at end of year	0	0	0
Benefit obligation at end of year	3.1	2.1	2.4
Funded status at end of year	($3.10)	($2.10)	($2.40)

Employee_Benefit_Plans_Compone

Employee Benefit Plans Components of Net Period Benefit Cost and other Amounts Recognized in Equity (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Balance Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$2.10	$1.90	$1.70
Amortization of prior service cost	0	0	0
Interest cost	0.3	0.2	0.1
Expected return on plan assets	-0.2	-0.1	0
Net periodic benefit cost	2.2	2	1.8
Prior service cost addition (amortization)	0	0	-0.1
Actuarial (gain) loss	0.7	0.3	0
Experience loss	0	0	0.1
Total changes recognized in other comprehensive loss	0.7	0.3	0
Retiree Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.2	0.3	0.1
Amortization of prior service cost	0.1	0.2	0.1
Interest cost	0.1	0.1	0.1
Expected return on plan assets	0	0	0
Net periodic benefit cost	0.4	0.6	0.3
Prior service cost addition (amortization)	-0.2	-0.2	1.3
Actuarial (gain) loss	0.7	-0.6	0.8
Experience loss	0	0	0
Total changes recognized in other comprehensive loss	$0.50	($0.80)	$2.10

Employee_Benefit_Plans_Weighte

Employee Benefit Plans Weighted Average Assumptions Used To Determine Benefit Obligation (Details) (Benefit Obligations)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Balance Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.00%	5.00%	4.00%
Rate of compensation increase	3.00%	4.00%	4.00%
Retiree Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.00%	5.00%	4.00%
Health care cost trend rate:
Initial rate	7.50%	7.00%	7.50%
Ultimate rate	5.00%	5.00%	5.00%
Years to ultimate	5 years	4 years	5 years

Employee_Benefit_Plans_Weighte1

Employee Benefit Plans Weighted Average Assumptions Used To Determine Net Periodic Benefit Cost (Details) (Net Periodic Benefit)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Balance Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.00%	4.00%	4.75%
Expected long-term rate of return on plan assets	4.75%	4.25%	4.50%
Rate of compensation increase	4.00%	4.00%	4.00%
Retiree Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.00%	4.00%	4.75%
Health care cost trend rate:
Initial rate	7.00%	7.50%	7.50%
Ultimate rate	5.00%	5.00%	5.00%
Years to ultimate	4 years	5 years	5 years

Employee_Benefit_Plans_Anticip

Employee Benefit Plans Anticipated Benefit Payments to Participants from Cash Balance Plan in Future Years (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
2015	$5.10
Cash Balance Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer	0.2	2.5	2.1
2015	0.3
2016	0.4
2017	0.5
2018	0.6
2019	0.8
2020-2024	6.5
Retiree Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer	0	0.1	0
2015	0.1
2016	0.1
2017	0.1
2018	0.1
2019	0.1
2020-2024	$1

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net cash from operating activities included:
Interest paid	$22.50	$26.70	$32.90
Income taxes paid	5	3.7	0
Noncash investing and financing activities include:
Capital expenditures included in accounts payable	2.9	10.2	1.2
PP&E derecognized in sale leaseback	0	0	-4.7
PP&E additions resulting from a capital lease	$1.70	$1.20	$1

Leasing_Arrangements_Additiona

Leasing Arrangements - Additional Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Store
Leases Disclosure [Line Items]
Number of convenience stores	254
Operating Leases, Rent Expense	$25.40	$24	$23.50
Marathon
Leases Disclosure [Line Items]
Number of convenience stores	135
Number of stores under lease	133

Leasing_Arrangements_Future_Mi

Leasing Arrangements Future Minimum Commitments for Lease Obligations (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Capital Leases
2015	$1.20
2016	1.2
2017	1
2018	0.9
2019	0.9
Thereafter	9.2
Total	14.4
Less: amount representing interest	-9.6
Present value of net minimum lease payments	4.8
Operating Leases
2015	22.7
2016	23.4
2017	22.7
2018	22.2
2019	21.8
Thereafter	133
Total	245.8
Total Leases
2015	23.9
2016	24.6
2017	23.7
2018	23.1
2019	22.7
Thereafter	142.2
Total	260.2
Present value of net minimum lease payments	$250.60

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Line Items]
Accrual for Environmental Loss Contingencies, Undiscounted, Next Twelve Months	$6.30
Accrual for Environmental Loss Contingencies, Undiscounted, Second Year	0.3
Accrual for Environmental Loss Contingencies, Undiscounted, Third Year	0.2
Accrual for Environmental Loss Contingencies, Undiscounted, Fourth Year	0.2
Accrual for Environmental Loss Contingencies, Undiscounted, Fifth Year	0.2
Accrual for Envrionmental Loss Contingencies, Undiscounted, after fifth year	2.1
Accrual for Environmental Loss Contingencies, Gross	9.3
Accrual for Environmental Loss Contingencies, Discount	0.6
Accrual for Environmental Loss Contingencies	8.7
Super America Franchising Company
Commitments and Contingencies Disclosure [Line Items]
Period for license agreements	10 years
Groundwater Contamination [Member]
Commitments and Contingencies Disclosure [Line Items]
Accrual for Environmental Loss Contingencies, Undiscounted, Next Twelve Months	0.5
Accrual for Environmental Loss Contingencies, Undiscounted, Second Year	0.3
Accrual for Environmental Loss Contingencies, Undiscounted, Third Year	0.2
Accrual for Environmental Loss Contingencies, Undiscounted, Fourth Year	0.2
Accrual for Environmental Loss Contingencies, Undiscounted, Fifth Year	0.2
Accrual for Envrionmental Loss Contingencies, Undiscounted, after fifth year	2.1
Accrual for Environmental Loss Contingencies, Gross	3.5
Accrual for Environmental Loss Contingencies, Discount	0.6
Accrual for Environmental Loss Contingencies	2.9	1.5
Period of remediation liabilities	23 years
Receivables for recoverable costs	0.2	0.1
Accrual for Environmental Loss Contingencies, Discount Rate	2.55%
Wastewater Lagoon [Member]
Commitments and Contingencies Disclosure [Line Items]
Accrual for Environmental Loss Contingencies, Undiscounted, Next Twelve Months	5.8
Accrual for Environmental Loss Contingencies, Undiscounted, Second Year	0
Accrual for Environmental Loss Contingencies, Undiscounted, Third Year	0
Accrual for Environmental Loss Contingencies, Undiscounted, Fourth Year	0
Accrual for Environmental Loss Contingencies, Undiscounted, Fifth Year	0
Accrual for Envrionmental Loss Contingencies, Undiscounted, after fifth year	0
Accrual for Environmental Loss Contingencies, Gross	5.8
Accrual for Environmental Loss Contingencies, Discount	0
Accrual for Environmental Loss Contingencies	$5.80

Segment_Information_Additional

Segment Information - Additional Information (Details)	12 Months Ended
	Dec. 31, 2014
	Segment
	Store
Segment Reporting Information [Line Items]
Reportable operating segments	2
Number of convenience stores	254
Retail
Segment Reporting Information [Line Items]
Number of convenience stores	165

Operating_Results_for_Operatin

Operating Results for Operating Segments (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues
Revenues	$1,059.80	$1,547.40	$1,602.50	$1,346.30	$1,292.10	$1,440.90	$1,131.20	$1,115	$5,556	$4,979.20	$4,653.90
Income (loss) from operations	27.1	104.8	65.6	77.8	33.8	27.5	52.6	132.2	275.3	246.1	569.3
Income from equity method investment									2.2	10	12.3
Depreciation and amortization									41.9	38.1	33.2
Capital expenditures									44.8	96.6	30.9
Total revenues
Revenues
Revenues									5,556	4,979.20	4,653.90
Refining
Revenues
Revenues									4,165.60	3,520.20	3,171.50
Income (loss) from operations									303.5	263.1	705.6
Income from equity method investment									2.2	10	12.3
Depreciation and amortization									33.7	30.4	25.4
Capital expenditures									35.4	88.7	24.2
Refining | Elimination of intersegment revenues
Revenues
Revenues									932.1	1,015.80	1,041.10
Refining | Total revenues
Revenues
Revenues									5,097.70	4,536	4,212.60
Retail
Revenues
Revenues									1,390.40	1,459	1,482.40
Income (loss) from operations									22.9	15.2	8.7
Income from equity method investment									0	0	0
Depreciation and amortization									7.3	7.1	6.6
Capital expenditures									8.8	7.7	4.6
Retail | Total revenues
Revenues
Revenues									1,390.40	1,459	1,482.40
Other
Revenues
Revenues									0	0	0
Income (loss) from operations									-51.1	-32.2	-145
Income from equity method investment									0	0	0
Depreciation and amortization									0.9	0.6	1.2
Capital expenditures									0.6	0.2	2.1
Other | Elimination of intersegment revenues
Revenues
Revenues									-932.1	-1,015.80	-1,041.10
Other | Total revenues
Revenues
Revenues									($932.10)	($1,015.80)	($1,041.10)

Total_Assets_by_Segment_Detail

Total Assets by Segment (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Segment Reporting Information [Line Items]
Equity method investment	$80.70	$86.20
Total Assets	1,180.40	1,117.80
Refining
Segment Reporting Information [Line Items]
Total Assets	932.9	875.6
Retail
Segment Reporting Information [Line Items]
Total Assets	134	138.2
Corporate/Other
Segment Reporting Information [Line Items]
Total Assets	$113.50	$104

Reorganization_and_Related_Cos2

Reorganization and Related Costs (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2012
Restructuring and Related Activities [Abstract]
Reorganization and related costs	$12.90	$1.40
Restructuring Cost and Reserve [Line Items]
Reorganization and related costs incurred during period	12.9
Less: non-cash equity based awards with accelerated vesting	-4.8
Ending liability for cash portion of reorganization costs	0.8
Employee Severance
Restructuring Cost and Reserve [Line Items]
Cash payments made to severed employees	($7.30)

Supplementary_Quarterly_Financ2

Supplementary Quarterly Financial Information (Unaudited) (Details) (USD $)	3 Months Ended								5 Months Ended	7 Months Ended	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jul. 31, 2012	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Revenue	$1,059.80	$1,547.40	$1,602.50	$1,346.30	$1,292.10	$1,440.90	$1,131.20	$1,115			$5,556		$4,979.20		$4,653.90
Operating income	27.1	104.8	65.6	77.8	33.8	27.5	52.6	132.2			275.3		246.1		569.3
Net income	$16	$96.20	$57.90	$71.50	$20.60	$27.20	$63.90	$119.40	$126.90	$70.70	$241.60	[1]	$231.10	[1]	$197.60
Earnings per unit, Basic (in dollars per share)	$0.17	$1.04	$0.62	$0.77							$2.61		$2.51		$1.38
Earnings per unit, Diluted (in dollars per share)	$0.17	$1.04	$0.62	$0.77							$2.61		$2.51		$1.38
Earnings per common unit (in dollars per share)					$0.22	$0.30	$0.70	$1.30					$2.51
[1]	(a) for 2012 calculations, net income available to common unitholders excludes earnings attributable to the period prior to our IPO date of July 31, 2012