Fair Value Measurements - Fair Value Recognition - Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reconciliation of the beginning and ending balances of liabilities measured at fair value using significant unobservable inputs (Level 3)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income [Extensible List]	Unrealized Gain (Loss) on Commodity Contracts	Unrealized Gain (Loss) on Commodity Contracts
Commodity swap contracts
Reconciliation of the beginning and ending balances of liabilities measured at fair value using significant unobservable inputs (Level 3)
Beginning Balance	$ (164)
Settlements, net	56
Total gain (loss)	108
Change in unrealized gain (loss) included in earnings	164
Embedded derivatives
Reconciliation of the beginning and ending balances of liabilities measured at fair value using significant unobservable inputs (Level 3)
Beginning Balance	(81)
Total gain (loss)	(3,227)
Ending Balance	(3,308)
Change in unrealized gain (loss) included in earnings	(3,227)
Warrants
Reconciliation of the beginning and ending balances of liabilities measured at fair value using significant unobservable inputs (Level 3)
Beginning Balance	40	$ 1,079
Total gain (loss)	(405)	(1,614)
Ending Balance	(445)	2,693
Change in unrealized gain (loss) included in earnings	$ (405)	$ (1,614)