Summary of Significant Accounting Policies - Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Accrued drilling, completion and facility costs	$ 42,805		$ 69,830
Accrued lease operating, gathering, transportation and processing expenses	9,039		6,970
Accrued general and administrative expenses	7,130		8,774
Accrued interest payable	18,901		6,758
Accrued merger transaction expenses	0		550
Trade payables	3,929		31,057
Operating lease liability	985	$ 300	0
Other	5,735		7,440
Total accounts payable and accrued liabilities	$ 88,524		$ 131,379