Supplemental Cash Flow Information - Non-cash Investing and Financing Activities (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020
Schedule Of Supplemental Cash Flow [Line Items]
Accrued capital expenditures	$ 996	$ 296
Lease liabilities arising from obtaining right-of-use assets	$ 9,156	57,452
Retail and Wholesale Acquisition [Member]
Schedule Of Supplemental Cash Flow [Line Items]
Net assets acquired		(12,335)
Asset Exchanges [Member] \| Circle K Stores Inc. [Member]
Schedule Of Supplemental Cash Flow [Line Items]
Net assets acquired		(55,552)
CST Fuel Supply Exchange Agreement [Member] \| Circle K Stores Inc. [Member]
Schedule Of Supplemental Cash Flow [Line Items]
Net assets acquired		$ (54,920)

The value of an asset or business acquired in a noncash (or part noncash) acquisition. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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