For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Disaggregation of oil, gas, and NGL production revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 282,012	$ 389,419	$ 806,035	$ 1,136,749
Revenue, Remaining Performance Obligation, Amount	0		0
Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	207,647	292,857	618,856	836,062
Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	49,555	64,047	125,128	194,384
NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	24,810	32,515	62,051	106,303
Midland Basin [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	217,966	295,265	631,818	840,978
Midland Basin [Member] \| Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	194,547	277,361	585,041	791,055
Midland Basin [Member] \| Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	23,304	17,780	46,559	49,821
Midland Basin [Member] \| NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	115	124	218	102
South Texas [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	64,046	94,154	174,217	295,771
South Texas [Member] \| Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	13,100	15,496	33,815	45,007
South Texas [Member] \| Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	26,251	46,267	78,569	144,563
South Texas [Member] \| NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 24,695	$ 32,391	$ 61,833	$ 106,201
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member]
Segment Reporting Information [Line Items]
Relative percentage	100.00%	100.00%	100.00%	100.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| Midland Basin [Member]
Segment Reporting Information [Line Items]
Relative percentage	77.00%	76.00%	78.00%	74.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| South Texas [Member]
Segment Reporting Information [Line Items]
Relative percentage	23.00%	24.00%	22.00%	26.00%