Acquisitions and Divestitures - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended	6 Months Ended
	Aug. 02, 2017	Jun. 15, 2017	Jun. 15, 2017	Mar. 31, 2018	Jun. 30, 2018	Jun. 30, 2017
Business Acquisition [Line Items]
Acquisition of oil and gas properties					$ 2,862	$ 108,179
Battlecat Oil & Gas, LLC
Business Acquisition [Line Items]
Purchase consideration of oil and gas properties			$ 59,800
Acquisition of oil and gas properties			55,000
Purchase consideration paid to acquire proved reserves			56,300
Purchase consideration paid to acquire unproved reserves			2,900
Purchase consideration paid to acquire unevaluated acreage and other assets			600
Asset retirement obligations recorded with the acquisition of properties		$ 200	200
Fair value of net assets acquired			59,600
Acquisition costs			$ 1,500
Effective date of acquisition			Apr. 01, 2017
SN Marquis LLC
Business Acquisition [Line Items]
Purchase consideration of oil and gas properties			$ 50,000
Acquisition of oil and gas properties			44,000
Purchase consideration paid to acquire proved reserves			48,000
Purchase consideration paid to acquire unproved reserves			600
Purchase consideration paid to acquire unevaluated acreage and other assets			1,400
Asset retirement obligations recorded with the acquisition of properties		$ 1,900	1,900
Fair value of net assets acquired			48,100
Acquisition costs			$ 1,200
Effective date of acquisition			Jan. 01, 2017
Series B Convertible Participating Preferred Stock | Battlecat Oil & Gas, LLC
Business Acquisition [Line Items]
Number of shares issued in connection with acquisition		1,184,632	1,184,632
Preferred Stock, par value (in dollars per share)		$ 0.001	$ 0.001
Value of shares issued in connection with acquisition			$ 4,800
Series B Convertible Participating Preferred Stock | SN Marquis LLC
Business Acquisition [Line Items]
Number of shares issued in connection with acquisition		1,500,000	1,500,000
Value of shares issued in connection with acquisition			$ 6,000
Fort Worth, Texas
Business Acquisition [Line Items]
Acquisition price of an office building	$ 10,000
Fort Worth, Texas | Other Expense
Business Acquisition [Line Items]
Impairment charge				$ 1,600