Reserve and Related Financial Data (SMOG) - Unaudited - Standardized Measure of Discounted Future Net Cash Flow (Details) MBoe in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) MBoe $ / bbl $ / MMBTU	Dec. 31, 2018 USD ($) MBoe $ / bbl $ / MMBTU	Dec. 31, 2017 USD ($) MBoe $ / bbl $ / MMBTU	Dec. 31, 2016 USD ($)
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]
Proved developed reserve quantities | MBoe	17,957	11,588	6,160
Future crude oil, natural gas, and NGL sales	$ 1,042,118	$ 1,049,141	$ 595,874
Future severance tax and ad valorem taxes	(73,627)	(70,248)	(40,225)
Future income tax expense	(143,599)	(144,421)	(1,151)
Future net cash flows	824,892	834,472	554,498
10% annual discount	(359,258)	(391,013)	(238,030)
Standardized measure of discounted future net cash flows	465,634	443,459	316,468	$ 185,752
Standardized measure of discounted future net cash flows attributable to temporary equity	$ 186,999	$ 0	$ 0
Oil (per Bbl)
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]
Prices used in determination of standardized measure (in dollars per unit) | $ / bbl	51.01	61.31	47.80
Natural gas (per Mcf)
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]
Prices used in determination of standardized measure (in dollars per unit) | $ / MMBTU	1.51	2.51	2.74
NGLs (per Bbl)
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]
Prices used in determination of standardized measure (in dollars per unit) | $ / bbl	14.39	23.98	18.56