Revenue from Contracts with Customers Disaggregation of oil, gas, and NGL production revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 1,585,750	[1]	$ 1,636,357	[2]	$ 1,253,783	[3]
Concentration Risk, Percentage	100.00%	[1]	100.00%	[2]	100.00%	[3]
Revenue, Remaining Performance Obligation, Amount	$ 0
Midland Basin [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	1,195,736	[1]	$ 1,064,607	[2]	$ 482,060	[3]
South Texas [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 390,014	[1]	514,514	[2]	610,485	[3]
Rocky Mountain [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax			$ 57,236	[2]	$ 161,238	[3]
Revenue Benchmark [Member] | Geographic Concentration Risk [Member] | Midland Basin [Member]
Segment Reporting Information [Line Items]
Concentration Risk, Percentage	75.00%	[1]	65.00%	[2]	38.00%	[3]
Revenue Benchmark [Member] | Geographic Concentration Risk [Member] | South Texas [Member]
Segment Reporting Information [Line Items]
Concentration Risk, Percentage	25.00%	[1]	32.00%	[2]	49.00%	[3]
Revenue Benchmark [Member] | Geographic Concentration Risk [Member] | Rocky Mountain [Member]
Segment Reporting Information [Line Items]
Concentration Risk, Percentage			3.00%	[2]	13.00%	[3]
Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 1,183,212		$ 1,065,676		$ 654,250
Oil production revenue [Member] | Midland Basin [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	1,119,786		938,004		419,732
Oil production revenue [Member] | South Texas [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	63,426		72,821		82,674
Oil production revenue [Member] | Rocky Mountain [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax			54,851		151,844
Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	262,529		354,450		369,410
Gas production revenue [Member] | Midland Basin [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	75,827		125,603		61,781
Gas production revenue [Member] | South Texas [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	186,702		227,252		301,780
Gas production revenue [Member] | Rocky Mountain [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax			1,595		5,849
NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	140,009		216,231		230,123
NGL production revenue [Member] | Midland Basin [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	123		1,000		547
NGL production revenue [Member] | South Texas [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 139,886		214,441		226,031
NGL production revenue [Member] | Rocky Mountain [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax			$ 790		$ 3,545

[1] Note: Amounts may not calculate due to rounding.

[2] Note: Amounts may not calculate due to rounding.

[3] Note: Amounts may not calculate due to rounding.