Related Party Transactions - Schedule of Supplemental Balance Sheet Information for CST Fuel Supply (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Supplemental Balance Sheet Information [Line Items]
Current assets	$ 63,495	$ 50,862
Current liabilities	112,636	88,448
CST Brands Inc. [Member]
Supplemental Balance Sheet Information [Line Items]
Current assets	58,049	8,571
Current liabilities	$ 123,102	$ 58,083

Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=118951113&loc=d3e6801-107765

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.9)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765

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