Receivables - Receivables (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 9,880	$ 23,893
Oil and gas joint interest billing receivables	777	867
Allowance for bad debts	(203)	(237)
Receivables, net	9,677	23,656
Funds held by qualified intermediary
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	14,703
Oil and gas revenue accrual receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	2,374	3,745
Receivables and accrued interest
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 5,244	$ 2,448
Notes receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average interest rates	12.52%	11.31%
Total	$ 1,485	$ 2,130