Fair Value Measurements - Commodity Swap Contracts (Details) - Not Designated as Hedging Instrument - Level 3	Jun. 30, 2020	Dec. 31, 2019
Commodity swaps | Minimum | Valuation Technique, Discounted Cash Flow | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.30	1.76
Commodity swaps | Minimum | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.80	0.79
Commodity swaps | Minimum | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.32	1.32
Commodity swaps | Maximum | Valuation Technique, Discounted Cash Flow | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.47	1.88
Commodity swaps | Maximum | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.58	1.16
Commodity swaps | Maximum | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.58	2.30
Commodity swaps | Weighted Average | Valuation Technique, Discounted Cash Flow | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.40	1.81
Commodity swaps | Weighted Average | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.96	0.91
Commodity swaps | Weighted Average | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.92	1.78
Fueling agreements | Minimum | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input		0.79
Fueling agreements | Minimum | Valuation Technique, Discounted Cash Flow | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.30	1.76
Fueling agreements | Minimum | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.80
Fueling agreements | Minimum | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.32	1.32
Fueling agreements | Maximum | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input		1.16
Fueling agreements | Maximum | Valuation Technique, Discounted Cash Flow | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.47	1.88
Fueling agreements | Maximum | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.58
Fueling agreements | Maximum | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	2.58	2.30
Fueling agreements | Weighted Average | Valuation Technique, Discounted Cash Flow | ULSD Gulf Coast Forward Curve
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.40	1.81
Fueling agreements | Weighted Average | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 3 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.96	0.91
Fueling agreements | Weighted Average | Valuation Technique, Discounted Cash Flow | Historical Differential to PADD 5 Diesel
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	1.92	1.78