Summary of Accounts Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accounts Receivable and Major Customers [Line Items]
Customers	$ 20,489	$ 23,481
Joint interest partners	7,238	18,381
Other	3,789	7,658
Accounts Receivable, Gross, Current, Total	31,516	49,520
Less: Allowance for doubtful accounts	(2,421)	(1,555)
Accounts receivable, net of allowance for doubtful accounts	$ 29,095	$ 47,965