Asset Exchange Transactions With Circle K - Schedule of Acquisition of Properties in Closed Asset Exchange Transaction (Details) - USD ($) $ in Thousands			9 Months Ended
		May 21, 2019	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Principal payments received on notes receivable			$ 803	$ 718
CK Properties [Member] | First Asset Exchange [Member]
Business Acquisition [Line Items]
Property and equipment, net		$ 35,345
Right-of-use assets, net		1,956
Total assets		37,301
Current portion of operating lease obligations		563
Operating lease obligations, less current portion		1,393
Deferred income taxes		(2,282)
Asset retirement obligations		1,887
Total liabilities		1,561
Net assets acquired		35,740
Net decrease in net assets		(1,456)
Principal payments received on notes receivable	[1]	234
Income tax liability incurred on sale		(5,135)
Net charge to equity		(6,357)
CK Properties [Member] | Second Asset Exchange [Member]
Business Acquisition [Line Items]
Property and equipment, net		36,891
Right-of-use assets, net		781
Total assets		37,672
Current portion of operating lease obligations		241
Operating lease obligations, less current portion		540
Deferred income taxes		(2,368)
Asset retirement obligations		1,617
Total liabilities		30
Net assets acquired		37,642
Net decrease in net assets		(146)
Principal payments received on notes receivable	[1]	1,171
Income tax liability incurred on sale		(2,078)
Net charge to equity		$ (1,053)

[1] Because the fair value of the properties divested to Circle K was $0.2 million greater than the fair value of the properties acquired from Circle K in the First Asset Exchange and $1.2 million greater than the fair value of the properties acquired from Circle K in the Second Asset Exchange, we recognized a receivable for $1.4 million.