(7) Equity Investment in Sunrise Energy (Detail) - Condensed Balance Sheet (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets	$ 34,863	$ 48,876
	229,207	232,428
Total liabilities	67,198	71,435
	229,207	232,428
Sunrise Energy Segment [Member]
Current assets	1,754	1,916
Oil and gas properties, net	6,934	6,236
	8,688	8,152
Total liabilities	762	1,558
Members' capital	7,926	6,594
	$ 8,688	$ 8,152

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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