Derivative Instruments - Offsetting Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Total Derivative Assets
Offsetting Assets [Line Items]
Gross Assets	$ 2,649	$ 1,073
Gross Amounts Offset	(2,634)	(503)
Net Assets	15	570
Cash Collateral Offset	0	0
Net Amount Presented	15	570
Total Current Derivative Assets
Offsetting Assets [Line Items]
Gross Assets	2,649	740
Gross Amounts Offset	(2,634)	(276)
Net Assets	15	464
Cash Collateral Offset	0	0
Net Amount Presented	15	464
Non-trading commodity derivatives
Offsetting Assets [Line Items]
Gross Assets	2,647	570
Gross Amounts Offset	(2,632)	(275)
Net Assets	15	295
Cash Collateral Offset	0	0
Net Amount Presented	15	295
Trading commodity derivatives
Offsetting Assets [Line Items]
Gross Assets	2	170
Gross Amounts Offset	(2)	(1)
Net Assets	0	169
Cash Collateral Offset	0	0
Net Amount Presented	0	169
Total Non-current Derivative Assets
Offsetting Assets [Line Items]
Gross Assets	0	333
Gross Amounts Offset	0	(227)
Net Assets	0	106
Cash Collateral Offset	0	0
Net Amount Presented	0	106
Non-trading commodity derivatives
Offsetting Assets [Line Items]
Gross Assets	0	333
Gross Amounts Offset	0	(227)
Net Assets	0	106
Cash Collateral Offset	0	0
Net Amount Presented	0	106
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