Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Disaggregated Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 851,135	$ 1,026,204	$ 829,691
Lease bonus - mineral acreage	4,062	1,711	2,489
Realized gain on derivatives	38,937	9,482	2,334
Unrealized gain on derivatives	(32,008)	(53,727)	65,085
Total revenues	862,126	983,670	899,599
Oil
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	595,507	759,811	635,554
Natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	148,954	132,514	165,146
Third-party midstream services revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	64,932	59,110	21,920
Sales of purchased natural gas
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 41,742	$ 74,769	$ 7,071