Summary of Significant Accounting Policies - Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Accrued drilling, completion and facility costs	$ 92,905		$ 69,830
Accrued lease operating, gathering, transportation and processing expenses	7,308		6,970
Accrued general and administrative expenses	6,513		8,774
Accrued interest payable	18,930		6,758
Accrued merger transaction expenses	682		550
Prepayments from partners	794		862
Trade payables	1,192		31,057
Operating lease liability	517	$ 300	0
Other	6,921		6,578
Total accounts payable and other accrued liabilities	$ 135,762		$ 131,379