Summary of Significant Accounting Policies - Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Accrued drilling, completion and facility costs	$ 75,984		$ 69,830
Accrued lease operating, gathering, transportation and processing expenses	7,398		6,970
Accrued general and administrative expenses	7,326		8,774
Accrued interest payable	6,852		6,758
Accrued merger transaction expenses	0		550
Trade payables	13,757		31,057
Operating lease liability	730	$ 300	0
Other	7,762		7,440
Total accounts payable and accrued liabilities	$ 119,809		$ 131,379