Long-Term Debt - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Oct. 26, 2018	Sep. 30, 2018	Sep. 12, 2016
Debt Disclosure [Line Items]
Maximum borrowing capacity				$ 340,000
Debt Issuance Costs, Line of Credit Arrangements, Gross	$ 900	$ 1,700			$ 3,011
Write off of Deferred Debt Issuance Cost		800
Required covenant, current ratio	1.00
Interest Coverage Ratio, Maximum	3.00
Second Lien Facility	$ 200,000	200,000
Proceeds from Debt, Net of Issuance Costs	187,800
Debt Instrument, Unamortized Discount	4,000
Unamortized Debt Issuance Expense	$ 8,200
Debt Instrument, Discounted Percentage	98.00%
Revolving Credit Facility [Member]
Debt Disclosure [Line Items]
Maximum borrowing capacity			$ 450,000
Line of Credit Facility, Interest Rate at Period End	5.9586%
Required covenant, debt to EBITDAX ratio	3.50
Revolving Credit Facility [Member] | Minimum
Debt Disclosure [Line Items]
Credit facility interest rate option one, applicable margin rate over Adjusted LIBOR	2.00%
Revolving Credit Facility [Member] | Maximum
Debt Disclosure [Line Items]
Credit facility interest rate option one, applicable margin rate over Adjusted LIBOR	3.00%
Credit facility interest rate option two, applicable margin rate	4.00%
Revolving credit facility
Debt Disclosure [Line Items]
Letter of credit amount outstanding	$ 400	$ 800
Revolving credit facility | Letter of Credit
Debt Disclosure [Line Items]
Maximum borrowing capacity	$ 5,000
Letter of Credit
Debt Disclosure [Line Items]
Commitment fees for undrawn credit facility	0.50%
Second Lien Facility [Member]
Debt Disclosure [Line Items]
Credit facility interest rate option one, applicable margin rate over Adjusted LIBOR	7.00%
Credit facility interest rate option two, applicable margin rate	6.00%
Second Lien Facility, Initial Interest Rate	8.34%
Second Lien Facility, Effective Interest Rate	9.89%
Interest Payable One [Member] | Revolving Credit Facility [Member]
Debt Disclosure [Line Items]
Debt Instrument, Interest Payable Period	1 month
Interest Payable Two [Member] | Revolving Credit Facility [Member]
Debt Disclosure [Line Items]
Debt Instrument, Interest Payable Period	3 months
Interest Payable Three [Member] | Revolving Credit Facility [Member]
Debt Disclosure [Line Items]
Debt Instrument, Interest Payable Period	6 months
Year 2 [Member]
Debt Disclosure [Line Items]
Prepayment Premium	102.00%
Prepayment Premium, Change in Control	102.00%
Year 3 [Member]
Debt Disclosure [Line Items]
Prepayment Premium	101.00%
Prepayment Premium, Change in Control	101.00%