Summary of Significant Accounting Policies - Summary of Revenue Disaggregated by Type (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation Of Revenue [Line Items]
Total revenues	$ 133,425	$ 141,497
Natural Gas Sales [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	79,090	81,825
NGL Sales [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	18,549	21,248
Oil Sales [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	26,232	28,755
Brokered Natural Gas and Marketing Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	9,488	9,530
Other Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 66	$ 139