Summary of Significant Accounting Policies - Summary of Revenue Disaggregated by Type (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Total revenues	$ 115,405	$ 163,295	$ 339,513	$ 460,332
Natural Gas Sales [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	72,926	87,841	217,604	264,030
NGL Sales [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	18,439	20,200	44,949	60,841
Oil Sales [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	17,153	44,980	52,918	103,407
Brokered Natural Gas and Marketing Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	6,831	10,228	23,859	31,747
Other Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 56	$ 46	$ 183	$ 307