Supplemental Disclosures of Cash Flow Information - Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	$ 26,689	$ 25,058
Cash paid for income taxes	0	0
Cash paid for operating leases	595	0
Operating leases (1)	14,955	0
Non-cash investing and financing activities:
Accounts payable and accrued liabilities - oil and gas properties	87,109	79,792
Change in asset retirement obligations, net of disposals	(5,022)	7,887
Retirement of treasury stock	(1,506)	(1,490)
Properties exchanged in non-cash transactions	4,561	0
Issuance of common stock for Merger	$ 0	$ 484,000