Supplemental Cash Flow Information - Non-cash Investing and Financing Activities (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Schedule Of Supplemental Cash Flow [Line Items]
Lease liabilities arising from obtaining right-of-use assets	$ 9,156	$ 7,351
Asset Exchanges [Member] \| Circle K Stores Inc. [Member]
Schedule Of Supplemental Cash Flow [Line Items]
Net assets acquired		(10,965)
CST Fuel Supply Exchange Agreement [Member] \| Circle K Stores Inc. [Member]
Schedule Of Supplemental Cash Flow [Line Items]
Net assets acquired		$ (55,282)

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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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