Investment in Savoy (Condensed Balance Sheet - Savoy) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets	$ 81,987	$ 84,409
Total assets	575,628	579,585
Total liabilities	372,856	389,710
Total liabilities and stockholders' equity	575,628	$ 579,585
Savoy [Member]
Current assets	12,397
Oil and gas properties, net	26,549
Total assets	38,946
Total liabilities	5,617
Partners' capital	33,329
Total liabilities and stockholders' equity	$ 38,946