Derivative Instruments - Offsetting Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Total Derivative Assets
Offsetting Assets [Line Items]
Gross Assets	$ 4,006	$ 420
Gross Amounts Offset	(2,267)	(109)
Net Assets	1,739	311
Cash Collateral Offset	0	0
Net Amount Presented	1,739	311
Total Current Derivative Assets
Offsetting Assets [Line Items]
Gross Assets	3,773	420
Gross Amounts Offset	(2,095)	(109)
Net Assets	1,678	311
Cash Collateral Offset	0	0
Net Amount Presented	1,678	311
Non-trading commodity derivatives
Offsetting Assets [Line Items]
Gross Assets	3,759	308
Gross Amounts Offset	(2,094)	(105)
Net Assets	1,665	203
Cash Collateral Offset	0	0
Net Amount Presented	1,665	203
Trading commodity derivatives
Offsetting Assets [Line Items]
Gross Assets	14	112
Gross Amounts Offset	(1)	(4)
Net Assets	13	108
Cash Collateral Offset	0	0
Net Amount Presented	13	108
Total Non-current Derivative Assets
Offsetting Assets [Line Items]
Gross Assets	233	0
Gross Amounts Offset	(172)	0
Net Assets	61	0
Cash Collateral Offset	0	0
Net Amount Presented	61	0
Non-trading commodity derivatives
Offsetting Assets [Line Items]
Gross Assets	233	0
Gross Amounts Offset	(172)	0
Net Assets	61	0
Cash Collateral Offset	0	0
Net Amount Presented	61	0
Trading commodity derivatives
Offsetting Assets [Line Items]
Gross Assets	0	0
Gross Amounts Offset	0	0
Net Assets	0	0
Cash Collateral Offset	0	0
Net Amount Presented	$ 0	$ 0