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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 169,790	$ 406,854	$ 524,023	$ 747,330
Revenue, Remaining Performance Obligation, Amount	0		0
Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	119,516	304,144	411,209	543,205
Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	34,863	65,224	75,573	130,337
NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	15,411	37,486	37,241	73,788
Midland Basin [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	126,324	304,853	413,852	545,713
Midland Basin [Member] \| Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	114,358	288,447	390,494	513,694
Midland Basin [Member] \| Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	11,921	16,449	23,255	32,041
Midland Basin [Member] \| NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	45	(43)	103	(22)
South Texas [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	43,466	102,001	110,171	201,617
South Texas [Member] \| Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	5,158	15,697	20,715	29,511
South Texas [Member] \| Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	22,942	48,775	52,318	98,296
South Texas [Member] \| NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 15,366	$ 37,529	$ 37,138	$ 73,810
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	74.00%	75.00%	79.00%	73.00%
Revenue Benchmark [Member] \| Geographic Concentration Risk [Member] \| South Texas [Member]
Segment Reporting Information [Line Items]
Relative percentage	26.00%	25.00%	21.00%	27.00%