Investment in Sunrise Energy (Condensed Balance Sheet - Sunrise) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets	$ 86,524us-gaap_AssetsCurrent	$ 84,409us-gaap_AssetsCurrent
Total assets	576,536us-gaap_Assets	579,585us-gaap_Assets
Total liabilities	379,530us-gaap_Liabilities	389,710us-gaap_Liabilities
Total liabilities and stockholders' equity	576,536	579,585
Sunrise Energy [Member]
Current assets	2,659
Oil and gas properties, net	7,799
Total assets	10,458
Total liabilities	747
Members' capital	9,711
Total liabilities and stockholders' equity	$ 10,458

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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Oil and gas properties net of accumulated depreciation, depletion, amortization, impairment, and abandonment, carried under the successful effort method.

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