Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accrued Liabilities
Capital expenditures	$ 52,958	$ 32,372
Gathering, compression, processing, and transportation expenses	158,443	152,724
Marketing expenses	115,317	68,193
Interest expense, net	34,693	25,645
Accrued production and ad valorem taxes	30,488	37,371
Derivative settlements payable	72,354	3,425
Other	36,879	23,794
Total accrued liabilities	$ 501,132	$ 343,524