Revenues from Contracts with Customers - Disaggregation of Revenue by Identified Revenue Stream (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total Revenue		$ 683,911	$ 460,745
Natural Gas, NGLs and Oil Sales
Disaggregation of Revenue [Line Items]
Total Revenue		603,347	432,096
Natural Gas, NGLs and Oil Sales | Natural gas sales
Disaggregation of Revenue [Line Items]
Total Revenue		335,801	253,249
Natural Gas, NGLs and Oil Sales | NGLs sales
Disaggregation of Revenue [Line Items]
Total Revenue		230,408	143,239
Natural Gas, NGLs and Oil Sales | Oil sales
Disaggregation of Revenue [Line Items]
Total Revenue		37,138	35,608
Brokered Natural Gas, Marketing and Other
Disaggregation of Revenue [Line Items]
Total Revenue		80,564	28,649
Brokered Natural Gas, Marketing and Other | Natural gas sales
Disaggregation of Revenue [Line Items]
Total Revenue		69,462	24,875
Brokered Natural Gas, Marketing and Other | NGLs sales
Disaggregation of Revenue [Line Items]
Total Revenue		426	1,140
Brokered Natural Gas, Marketing and Other | Other marketing revenue
Disaggregation of Revenue [Line Items]
Total Revenue	[1]	$ 10,676	$ 2,634

[1] ⁾ The three months ended March 31, 2021 includes $8.8 million received as part of a capacity release agreement