Investment in Savoy (Condensed Balance Sheet - Savoy) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets	$ 62,274	$ 66,615
Other	20,010	11,416
Total assets	547,587	540,378
Total liabilities	335,141	333,558
Total liabilities and stockholders' equity	547,587	$ 540,378
Savoy [Member]
Current assets	6,604
Oil and gas properties, net	20,803
Total assets	28,414
Total liabilities	3,670
Partners' capital	24,744
Total liabilities and stockholders' equity	$ 28,414