Summary of Significant Accounting Policies - Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Accrued drilling, completion and facility costs	$ 69,830	$ 35,856
Accrued lease operating, gathering, transportation and processing expenses	6,970	4,360
Accrued general and administrative expenses	8,774	11,134
Accrued interest payable	6,758	6,484
Accrued merger transaction expenses	550	8,278
Prepayments from partners	862	2,524
Trade payables	31,057	10,067
Other	6,578	5,352
Total accounts payable and accrued liabilities	$ 131,379	$ 84,055