Equity Investment in Savoy (Narrative) (Details) (USD $)	1 Months Ended	12 Months Ended
	Oct. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2014
Cash distributions	$ 4,900,000	$ 8,109,000	$ 1,325,000
Minimum prior industry experience of petroleum engineering consultant		5 years
Savoy [Member]
Equity method investment ownership percentage		40.00%		45.00%
Cash distributions paid	$ 12,000,000