Equity Investment in Sunrise Energy (Condensed Balance Sheet - Sunrise) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets	$ 84,409us-gaap_AssetsCurrent	$ 40,170us-gaap_AssetsCurrent
Total assets	579,585us-gaap_Assets	259,199us-gaap_Assets
Total liabilities	389,710us-gaap_Liabilities	77,079us-gaap_Liabilities
Total liabilities and stockholders' equity	579,585	259,199
Sunrise Energy [Member]
Current assets	3,580	3,109
Oil and gas properties, net	7,130	6,781
Total assets	10,710	9,890
Total liabilities	1,080	756
Members' capital	9,630	9,134
Total liabilities and stockholders' equity	$ 10,710	$ 9,890

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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Amount of member capital in limited liability company (LLC).

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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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