Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 271,059	$ 482,743	$ 825,209	$ 1,587,880
Exploration And Production
Disaggregation of Revenue [Line Items]
Total revenues	215,636	432,720	668,849	1,438,235
Midstream Services
Disaggregation of Revenue [Line Items]
Total revenues	110,061	123,411	316,737	349,438
Operating Segments | Exploration And Production
Disaggregation of Revenue [Line Items]
Total revenues	215,636	432,720	668,849	1,438,235
Operating Segments | Exploration And Production | Crude oil revenues
Disaggregation of Revenue [Line Items]
Total revenues	155,052	318,564	448,904	964,662
Operating Segments | Exploration And Production | Purchased crude oil sales
Disaggregation of Revenue [Line Items]
Total revenues	35,442	77,018	144,719	330,594
Operating Segments | Exploration And Production | Natural gas and NGL revenues
Disaggregation of Revenue [Line Items]
Total revenues	24,525	25,906	63,631	105,594
Operating Segments | Exploration And Production | Purchased natural gas sales
Disaggregation of Revenue [Line Items]
Total revenues	308	2,334	4,909	6,590
Operating Segments | Exploration And Production | Other services revenues
Disaggregation of Revenue [Line Items]
Total revenues	309	8,898	6,686	30,795
Operating Segments | Midstream Services
Disaggregation of Revenue [Line Items]
Total revenues	55,423	50,023	156,360	149,645
Operating Segments | Midstream Services | Purchased crude oil sales
Disaggregation of Revenue [Line Items]
Total revenues	8,444	0	18,196	28
Operating Segments | Midstream Services | Crude oil, natural gas and NGL revenues
Disaggregation of Revenue [Line Items]
Total revenues	22,682	21,653	72,267	69,189
Operating Segments | Midstream Services | Produced and flowback water revenues
Disaggregation of Revenue [Line Items]
Total revenues	8,801	10,803	27,300	29,309
Operating Segments | Midstream Services | Total midstream service revenues
Disaggregation of Revenue [Line Items]
Total revenues	31,483	32,456	99,567	98,498
Operating Segments | Midstream Services | Crude oil, natural gas and NGL revenues
Disaggregation of Revenue [Line Items]
Total revenues	15,100	16,424	35,707	46,541
Operating Segments | Midstream Services | Freshwater revenues
Disaggregation of Revenue [Line Items]
Total revenues	396	1,143	2,890	4,578
Operating Segments | Midstream Services | Total midstream product revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 23,940	$ 17,567	$ 56,793	$ 51,147