Investment in Laramie Energy, LLC - Summarized Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
ASSETS
Current assets	$ 749,126						$ 749,126		$ 1,032,174
Current liabilities	875,703						875,703		1,034,322
REVENUE
Loss from operations	2,750			$ 18,405			(203,866)	$ 88,449
Net loss	(14,271)	$ (40,560)	$ (222,337)	(83,891)	$ 28,169	$ 61,092	(277,168)	5,370
Laramie Energy Company
ASSETS
Current assets	23,808						23,808		23,367
Non-current assets	366,610						366,610		393,575
Current liabilities	23,714						23,714		229,687
Non-current liabilities	291,138						291,138		$ 85,287
REVENUE
Natural gas and oil revenues	28,257			38,967			86,515	150,161
Loss from operations	(3,443)			(10,028)			(10,773)	(4,490)
Net loss	$ (12,643)			$ (12,586)			$ (26,418)	$ (18,139)