Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Capitalized Costs, Oil and Gas Producing Activities, Net	$ 2,020,873	$ 1,012,610
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	407,949
Cumulative effect of accounting change			$ (329)
Non-cash impairment of oil and gas properties	$ 0
Environmental Remediation Expense	$ 1,900	700
Contract Payment Term	1 month
Piceance [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties		9,100
DJ Basin, non-core [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties		$ 2,100
Additional Paid-In Capital [Member]
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect of accounting change			$ 180
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue, Contract Term	1 month
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue, Contract Term	19 years
Fifth Creek [Member]
Summary Of Significant Accounting Policies [Line Items]
Capitalized Costs, Oil and Gas Producing Activities, Net	$ 722,600