Investment in Savoy (Condensed Balance Sheet - Savoy) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets	$ 63,479	$ 66,615
Other	21,611	11,416
Total assets	540,083	540,378
Total liabilities	317,860	333,558
Total liabilities and stockholders' equity	540,083	$ 540,378
Savoy [Member]
Current assets	8,776
Oil and gas properties, net	19,429
Other	997
Total assets	29,202
Total liabilities	3,847
Partners' capital	25,355
Total liabilities and stockholders' equity	$ 29,202