Organization and Summary of Significant Accounting Policies - Summary Of Changes In Future Abandonment Liabilities (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations at January 1		$ 114,406	$ 96,178	$ 102,909
Accretion expense		6,985	5,886	6,086
Revisions	[1]	13,075	7,801	(12,755)
Plus: Additions for new assets		9,070	6,884	2,692
Less: Plugging costs and sold assets		(2,176)	(2,343)	(2,754)
Total asset retirement obligations at December 31		141,360	114,406	96,178
Less: Current portion of asset retirement obligations at December 31	[2]	4,374	2,612	1,742
Non-current portion of asset retirement obligations at December 31		$ 136,986	$ 111,794	$ 94,436

[1] Revisions primarily represent changes in the present value of liabilities resulting from changes in estimated costs and economic lives of producing properties.

[2] Balance is included in the caption “Accrued liabilities and other” in the consolidated balance sheets.