Asset Exchange Transaction With Circle K - Additional Information (Details) $ in Thousands	Dec. 17, 2018 USD ($) Store	Mar. 31, 2019 USD ($) Store	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Properties aggregate value | $		$ 793,831	$ 841,146
Circle K Stores Inc. [Member]
Business Acquisition [Line Items]
Number of Stores		47
Asset Exchange Agreement [Member]
Business Acquisition [Line Items]
Properties aggregate value | $	$ 184,500
Asset Exchange Agreement [Member] | Indemnification Obligations [Member]
Business Acquisition [Line Items]
Warranties and covenants period	18 months
Maximum amount exempted from indemnification obligations | $	$ 1,845
Maximum indemnification obligation | $	$ 39,900
Asset Exchange Agreement [Member] | U.S. Upper Midwest [Member]
Business Acquisition [Line Items]
Number of convenience and fuel retail stores currently owned and operated	17
Asset Exchange Agreement [Member] | Circle K Stores Inc. [Member]
Business Acquisition [Line Items]
Number of Stores	192
Expected period for closure of asset exchange agreement	24 months
Asset Exchange Agreement [Member] | Circle K Stores Inc. [Member] | U.S. Upper Midwest [Member]
Business Acquisition [Line Items]
Number of convenience and fuel retail stores currently leased and operated	56
Asset Exchange Agreement [Member] | Circle K Stores Inc. [Member] | Fee Site [Member]
Business Acquisition [Line Items]
Number of Stores	162
Asset Exchange Agreement [Member] | Circle K Stores Inc. [Member] | Leased Site [Member]
Business Acquisition [Line Items]
Number of Stores	30
Asset Exchange Agreement [Member] | Circle K Stores Inc. [Member] | CK Properties [Member]
Business Acquisition [Line Items]
Properties aggregate value | $	$ 184,500