Oil and Natural Gas Properties (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Oil And Natural Gas Properties [Line Items]
Impairment of proved and unproved oil and gas properties	$ 0	$ 833,000	$ 0	$ 833,000
Proved Oil and Natural Gas Properties
Oil And Natural Gas Properties [Line Items]
Depletion expenses	$ 13,900,000	12,700,000	$ 41,700,000	33,000,000
Unproved Oil and Gas Properties
Oil And Natural Gas Properties [Line Items]
Impairment of proved and unproved oil and gas properties		$ 800,000		$ 800,000
Unproved Oil and Gas Properties | Minimum
Oil And Natural Gas Properties [Line Items]
Unproved oil and gas lease term			3 years
Unproved Oil and Gas Properties | Maximum
Oil And Natural Gas Properties [Line Items]
Unproved oil and gas lease term			5 years