Revenue from Contracts with Customers - Impact of ASU 2014-09 Adoption (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Revenues	$ 302,283	$ 301,875	$ 76,236
Operating expenses:
Gathering and transportation	5,756	4,939	2,976
Amounts Without Adoption of ASU 2014-09
Revenues:
Revenues	304,736
Operating expenses:
Gathering and transportation	8,209
Accounting Standards Update 2014-09 | Effect of Change
Revenues:
Revenues	(2,453)
Operating expenses:
Gathering and transportation	(2,453)
Oil sales
Revenues:
Revenues	286,710	271,539	61,596
Oil sales | Amounts Without Adoption of ASU 2014-09
Revenues:
Revenues	285,894
Oil sales | Accounting Standards Update 2014-09 | Effect of Change
Revenues:
Revenues	816
Natural gas sales
Revenues:
Revenues	2,489	9,392	7,171
Natural gas sales | Amounts Without Adoption of ASU 2014-09
Revenues:
Revenues	4,640
Natural gas sales | Accounting Standards Update 2014-09 | Effect of Change
Revenues:
Revenues	(2,151)
Natural gas liquids sales
Revenues:
Revenues	13,084	$ 20,944	$ 7,469
Natural gas liquids sales | Amounts Without Adoption of ASU 2014-09
Revenues:
Revenues	14,202
Natural gas liquids sales | Accounting Standards Update 2014-09 | Effect of Change
Revenues:
Revenues	$ (1,118)