Debt and Financing Obligations - Financing Obligations (Details) $ in Thousands			3 Months Ended		6 Months Ended
	Jun. 29, 2016 USD ($) item location	Jun. 01, 2015 USD ($) item	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Feb. 24, 2016 USD ($)	Feb. 23, 2016 USD ($)	Dec. 31, 2015 USD ($)
Financing Obligations
Financing obligation			$ 152,371		$ 152,371				$ 89,790
Future Minimum Sublease Rentals
Unamortized fees			17,200		17,200				19,000
Write-off of a portion of the original issue discount and deferred financing fees					1,828
Amortization expenses					2,948	$ 2,927
Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations [Member] | Sale Leaseback Sites [Member]
Financing Obligations
Financing obligation	$ 62,500		62,500		62,500
Number of sites under financing obligation | location	30
Sale leaseback, gross proceeds	$ 63,500
Initial lease term	15 years
Number of 5-year options | item	2
Number of 10-year options | item	1
Sale leaseback financing fees	$ 1,000
Future Minimum Lease Payments
2016 (7/1/16 - 12/31/16)			2,205		2,205
2017			4,411		4,411
2018			4,411		4,411
2019			4,411		4,411
2020			4,411		4,411
Thereafter			46,286		46,286
Total			66,135		66,135
Future Minimum Sublease Rentals
2016 (7/1/16 - 12/31/16)			972		972
2017			1,315		1,315
2018			692		692
2019			256		256
2020			169		169
Total			3,404		3,404
Deferred financing fees capitalized			1,000		1,000
Unamortized fees			1,000		1,000
Capitol Petroleum Group
Financing Obligations
Financing obligation		$ 89,600	89,900		89,900
Number of sale-leaseback transactions | item		2
Number of sites under financing obligation | item		53
Lease rental payments			2,400	$ 800	4,700	800
Long-Term Debt Caption [Member]
Future Minimum Sublease Rentals
Unamortized fees			7,200		7,200				7,800
Interest Expense [Member]
Future Minimum Sublease Rentals
Amortization expenses			1,500	1,400	2,900	2,900
Interest Expense [Member] | Capitol Petroleum Group
Financing Obligations
Interest expense for sale-leaseback properties			2,400	$ 800	4,800	$ 800
Credit Agreement Maturing 2018 [Member]
Future Minimum Sublease Rentals
Total available commitments			1,775,000		1,775,000
Credit Agreement Maturing 2018 [Member] | Other Assets, Current and Noncurrent [Member]
Future Minimum Sublease Rentals
Unamortized fees			9,000		9,000				11,200
All Revolving credit facilities
Future Minimum Sublease Rentals
Total available commitments							$ 1,475,000
Working Capital Facility [Member]
Future Minimum Sublease Rentals
Total available commitments			900,000,000		900,000,000		900,000	$ 1,000,000	1,000,000
Working Capital Facility [Member] | Interest Expense [Member]
Future Minimum Sublease Rentals
Write-off of a portion of the original issue discount and deferred financing fees					1,800
Revolving Credit Facility [Member]
Future Minimum Sublease Rentals
Total available commitments			$ 575,000		$ 575,000		$ 575,000	$ 775,000	$ 775,000