Summary of Accounts Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Receivables [Abstract]
Customers	$ 23,481	$ 62,650
Joint interest partners	18,381	120,708
Other	7,658	6,549
Accounts Receivable, Gross, Current, Total	49,520	189,907
Less: Allowance for doubtful accounts	(1,555)	(280)
Accounts receivable, net of allowance for doubtful accounts	$ 47,965	$ 189,627