Acquisitions - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended			0 Months Ended	3 Months Ended	6 Months Ended	0 Months Ended		0 Months Ended					0 Months Ended						3 Months Ended	6 Months Ended		0 Months Ended			0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	May 19, 2014 Atlas Acquisition [Member]	Jun. 30, 2014 Atlas Acquisition [Member]	Jun. 30, 2014 Atlas Acquisition [Member]	May 19, 2014 Atlas Acquisition [Member] Covenant Not to Compete [Member]	May 19, 2014 Atlas Acquisition [Member] Covenant Not to Compete [Member]	May 19, 2014 Atlas Acquisition [Member] Buildings [Member]	May 19, 2014 Atlas Acquisition [Member] Equipment [Member] Minimum [Member]	May 19, 2014 Atlas Acquisition [Member] Equipment [Member] Maximum [Member]	May 19, 2014 Atlas Acquisition [Member] Wholesale Supply Contracts [Member] Contract	May 19, 2014 Atlas Acquisition [Member] Wholesale Supply Contracts [Member]	May 19, 2014 Atlas Acquisition [Member] Sub-Wholesaler Contract [Member] Contract	May 19, 2014 Atlas Acquisition [Member] Fee Sites [Member] Contract	May 19, 2014 Atlas Acquisition [Member] Leasehold Sites [Member] Contract	Apr. 28, 2014 Pinehurst [Member]	May 02, 2014 PMI Acquisition [Member]	Apr. 28, 2014 PMI Acquisition [Member]	Jun. 30, 2014 PMI Acquisition [Member]	Jun. 30, 2014 PMI Acquisition [Member]	Apr. 30, 2014 PMI Acquisition [Member] Store	May 02, 2014 PMI Acquisition [Member] Wholesale Fuel Supply Agreements [Member]	May 01, 2014 PMI Acquisition [Member] Wholesale Fuel Supply Agreements [Member]	Apr. 30, 2014 PMI Acquisition [Member] Consideration [Member]	May 02, 2014 PMI Acquisition [Member] Buildings [Member]	May 02, 2014 PMI Acquisition [Member] Equipment [Member] Minimum [Member]	May 02, 2014 PMI Acquisition [Member] Equipment [Member] Maximum [Member]
Subsequent Event [Line Items]
Membership interests of Pinehurst Petroleum, LLC																			100.00%
Purchase price consideration						$ 40,200,000													$ 4,000,000		$ 73,500,000
Accrued expenses and other current liabilities	11,544,000		11,544,000		8,059,000																						2,000,000
Business combination escrow deposit																					5,000,000
Business combination escrow deposit term																					25 months
Number of convenience stores																								87
Number of co-located stores																								9
Proceeds from divestiture of Lubricants business																				14,000,000
Effective date of divestiture of Lubricants business																							May 01, 2014
Estimated useful lives											20 years	5 years	15 years															20 years	5 years	15 years
Intangible asset amortized method								Straight-line basis															Straight-line basis
Fair value of intangible assets										1,000,000					14,000,000											15,000,000
Estimated useful lives									5 years					10 years											10 years
Revenue							28,400,000	28,400,000														173,800,000	173,800,000
Purchase agreement														52		1	9	6
Purchase price consideration excluding value of acquired short-term financing assets						35,000,000
Acquisition of short-term financing assets						5,200,000
Purchase agreement date								May 19, 2014
Proceeds from the sale of Lubricants Business			10,001,000			4,000,000
Wholesale supply contracts remaining average term														15 years
Short-term notes receivable weighted average maturity date						2015-06
Business acquisition description								(a) engaging in the wholesale distribution of motor fuel or owning or operating a retail motor fuel facility and/or convenience store within certain territories for one year after the closing date, and (b) constructing any new retail motor fuel facility and/or convenience stores within certain territories for five years after the closing date.
Acquisition costs	$ 5,600,000	$ 300,000	$ 5,900,000	$ 500,000