Related Party Transactions - Additional Information (Details) $ in Thousands			1 Months Ended		3 Months Ended	12 Months Ended
	May 31, 2018 USD ($) Retailsite	Mar. 31, 2018 USD ($) Retailsite	Sep. 30, 2017 Store	Jul. 31, 2016 USD ($) Store	Dec. 31, 2018 USD ($) Store Retailsite $ / gal	Dec. 31, 2018 USD ($) Store Property Retailsite $ / gal gal	Dec. 31, 2017 USD ($) Property	Dec. 31, 2016 USD ($)	Jun. 30, 2018 Store
Related Party Transaction [Line Items]
Accounts receivable from related parties					$ 9,697	$ 9,697	$ 14,459
Income from CST Fuel Supply equity interests						$ 14,948	14,906	$ 16,048
Number of sites sold | Store				79
Ownership interest						21.70%
Refund payment related to the sale by CST of California and Wyoming assets								17,528
Cost of services						$ 2,273,122	1,934,061	1,714,239
Payment of leasehold interest						485		2,900
Accounts payable to related parties					$ 25,045	25,045	25,512
Incentive distribution						1,579	4,337	3,392
Contributions from parent company						6,306	329
Rental income						85,642	86,314	80,594
Rent expense						$ 19,723	$ 19,472	19,656
Properties Disposed Upon FTC's Requirement [Member]
Related Party Transaction [Line Items]
Number of properties sold | Property						9	2
Consideration received on property sale							$ 6,700
Gain on sales of assets, net							$ 2,200
Wholesale Fuel Supply Contracts/Rights [Member] | CST Brands Inc. [Member]
Related Party Transaction [Line Items]
Equity method investment, ownership percentage					17.50%	17.50%	17.50%
Income from CST Fuel Supply equity interests						$ 14,900	$ 14,900	16,000
Amended and Restated Omnibus Agreement [Member]
Related Party Transaction [Line Items]
Cost and expenses incurred						$ 11,800	13,900	15,900
Circle K Stores Inc. [Member]
Related Party Transaction [Line Items]
Number of Stores | Store					47	47
Number of retail sites leased to related party | Store						73
Lessor leasing arrangements, operating leases, initial term					10 years	10 years
Purchases from related party						$ 2,200
Number of lease hold interest acquired In retail sites | Retailsite	3	3
Payment of leasehold interest	$ 500	$ 500
Amounts payable to fuel purchases and freight commissions to related parties					$ 4,300	4,300	7,000
Incentive distribution						1,600	4,300	3,400
Dividends cash						16,200	17,000	15,500
Circle K Stores Inc. [Member] | Properties Disposed Upon FTC's Requirement [Member]
Related Party Transaction [Line Items]
Contributions from parent company					6,300		300
Circle K Stores Inc. [Member] | Franchise [Member]
Related Party Transaction [Line Items]
Cost of services						1,000
Circle K Stores Inc. [Member] | Fuel Sales Transaction [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties					2,600	2,600	3,900
Circle K Stores Inc. [Member] | Fuel Supply Equity Interest Transaction [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties					$ 1,000	$ 1,000	1,200
Circle K Stores Inc. [Member] | Annual Commitment [Member]
Related Party Transaction [Line Items]
Fuel purchase agreements | gal						114,900,000
Fuel purchase commitments margin payable per gallon | $ / gal					0.05	0.05
Circle K Stores Inc. [Member] | Jet-Pep Assets Acquisition [Member]
Related Party Transaction [Line Items]
Number of Stores | Retailsite					99	99
Purchases from related party						$ 124,200	11,300
Circle K Stores Inc. [Member] | Fuel Supply To Franchised Holiday Stores [Member]
Related Party Transaction [Line Items]
Purchases from related party						49,900	1,900
Circle K Stores Inc. [Member] | Amended and Restated Omnibus Agreement [Member]
Related Party Transaction [Line Items]
Accounts payable to related parties					$ 20,200	20,200	18,300
Circle K Stores Inc. [Member] | Amended and Restated Omnibus Agreement [Member] | General and Administrative Expenses [Member]
Related Party Transaction [Line Items]
Severance, benefit, and retention costs						$ 800	7,100
CST Brands Inc. [Member]
Related Party Transaction [Line Items]
Equity method investment, ownership percentage					17.50%	17.50%
Number of sites sold | Store			61
Partners' Capital Account, Return of Capital				$ 18,200
Refund payment related to the sale by CST of California and Wyoming assets				$ 17,500
Rent expense						$ 700	$ 700	$ 600
CST Brands Inc. [Member] | CST Marketing and Supply [member]
Related Party Transaction [Line Items]
Ownership interest						100.00%
CST Brands Inc. [Member] | Annual Commitment [Member]
Related Party Transaction [Line Items]
Initial term of agreement						10 years
CST Brands Inc. [Member] | Wholesale Fuel Supply Contracts/Rights [Member]
Related Party Transaction [Line Items]
Number of Stores | Store					21	21
Equity method investment, ownership percentage					17.50%	17.50%	17.50%	17.50%
Purchases from related party						$ 18,100	$ 23,800	$ 20,400
Couche-Tard [Member]
Related Party Transaction [Line Items]
Percentage of commission					2.57%	2.57%
Commission on transportation costs						$ 500
DMS [Member]
Related Party Transaction [Line Items]
Number of Stores | Store									43
Accounts receivable from related parties					$ 5,600	5,600	9,300
Accounts payable to related parties					3,800	3,800
Write off of deferred rent income charges						2,400
Earn-out payment receivable							800
Topper And Entities [Member]
Related Party Transaction [Line Items]
Accounts payable to related parties					$ 400	400	200
Rental income						300	500	500
Rent expense						1,000	900	900
Topper And Entities [Member] | Environmental Remediation [Member]
Related Party Transaction [Line Items]
Cost of services						1,800	$ 1,500	1,600
DMR [Member]
Related Party Transaction [Line Items]
Number of properties sold | Property							29
Consideration received on property sale							$ 18,900
Gain on sales of assets, net							800
Company Affiliated with a Member of the Board [Member]
Related Party Transaction [Line Items]
Cost of services related to public relations and website consulting						$ 100	$ 100	$ 100