Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 147,416	$ 234,382	$ 371,704	$ 450,720
Lease bonus - mineral acreage	4,062	0	4,062	0
Realized gain on derivatives	44,110	1,165	54,977	4,435
Unrealized (loss) gain on derivatives	(132,668)	6,157	3,762	(39,562)
Total revenue	62,920	241,704	434,505	415,593
Oil revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	94,174	189,085	263,759	343,288
Natural gas revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	24,593	21,975	52,922	61,041
Third-party midstream services revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	14,668	14,359	30,498	26,197
Sales of purchased natural gas
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	13,981	8,963	24,525	20,194
Total revenues from contracts with customers
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 147,416	$ 234,382	$ 371,704	$ 450,720