Derivative Activities - Effects of Derivatives on Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
Derivative Fair Value (Loss) Income	$ (124,690)	$ 74,676	$ 102,182	$ 208,190
Contingent Consideration
Derivative [Line Items]
Derivative Fair Value (Loss) Income	430		430
Swaptions
Derivative [Line Items]
Derivative Fair Value (Loss) Income	(14,166)	10,358	(15,520)	39,451
Collars
Derivative [Line Items]
Derivative Fair Value (Loss) Income	(16,893)	356	(14,336)	(3,590)
Three Way Collars
Derivative [Line Items]
Derivative Fair Value (Loss) Income	(20,705)		(38,267)	0
Calls
Derivative [Line Items]
Derivative Fair Value (Loss) Income	(255)	(224)	(12)	(224)
Basis Swaps
Derivative [Line Items]
Derivative Fair Value (Loss) Income	15,587	3,448	31,750	7,801
Commodity | Swaps
Derivative [Line Items]
Derivative Fair Value (Loss) Income	(91,425)	60,090	142,413	161,799
Freight | Swaps
Derivative [Line Items]
Derivative Fair Value (Loss) Income	$ 2,737	$ 648	$ (4,276)	$ 2,953