Organization and Summary of Significant Accounting Policies - Components of Inventories (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Components Of Inventory [Line Items]
Tubular goods and equipment	$ 13,590	$ 15,665
Crude oil	33,153	25,605
Total	$ 46,743	$ 41,270