Equity Investment in Savoy (Proved Reserves Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Future cash inflows:
Cash inflows	$ 63,738	$ 147,805
Future production costs	(16,635)	(24,446)
Future development costs	(1,850)	(3,073)
Future income tax (none since Savoy is a pass-through entity for income tax purposes)
Future net cash flows	45,253	120,286
10% annual discount for estimated timing of cash flows	(11,153)	(29,486)
Standardized measure of discounted future net cash flows	34,100	90,800
Oil [Member]
Future cash inflows:
Cash inflows	60,190	141,244
Natural Gas Liquids [Member]
Future cash inflows:
Cash inflows	1,624	4,220
Natural Gas [Member]
Future cash inflows:
Cash inflows	1,924	2,341
Proved Developed [Member]
Future cash inflows:
Cash inflows	44,119	74,498
Future production costs	(12,886)	(12,213)
Future development costs	(60)
Future income tax (none since Savoy is a pass-through entity for income tax purposes)
Future net cash flows	31,173	62,285
10% annual discount for estimated timing of cash flows	(7,125)	(14,375)
Standardized measure of discounted future net cash flows	24,048	47,910
Proved Developed [Member] | Oil [Member]
Future cash inflows:
Cash inflows	41,660	70,582
Proved Developed [Member] | Natural Gas Liquids [Member]
Future cash inflows:
Cash inflows	1,256	2,551
Proved Developed [Member] | Natural Gas [Member]
Future cash inflows:
Cash inflows	1,203	1,365
Proved Undeveloped (PUDs) [Member]
Future cash inflows:
Cash inflows	19,619	73,307
Future production costs	(3,749)	(12,233)
Future development costs	(1,790)	(3,073)
Future income tax (none since Savoy is a pass-through entity for income tax purposes)
Future net cash flows	14,080	58,001
10% annual discount for estimated timing of cash flows	(4,028)	(15,111)
Standardized measure of discounted future net cash flows	10,052	42,890
Proved Undeveloped (PUDs) [Member] | Oil [Member]
Future cash inflows:
Cash inflows	18,530	70,662
Proved Undeveloped (PUDs) [Member] | Natural Gas Liquids [Member]
Future cash inflows:
Cash inflows	368	1,669
Proved Undeveloped (PUDs) [Member] | Natural Gas [Member]
Future cash inflows:
Cash inflows	721	976
NYMEX Strip Prices [Member]
Future cash inflows:
Cash inflows	39,642
Future production costs	(12,860)
Future development costs	(1,858)
Future income tax (none since Savoy is a pass-through entity for income tax purposes)
Future net cash flows	24,924
10% annual discount for estimated timing of cash flows	(5,944)
Standardized measure of discounted future net cash flows	18,980
NYMEX Strip Prices [Member] | Oil [Member]
Future cash inflows:
Cash inflows	37,007
NYMEX Strip Prices [Member] | Natural Gas Liquids [Member]
Future cash inflows:
Cash inflows	1,037
NYMEX Strip Prices [Member] | Natural Gas [Member]
Future cash inflows:
Cash inflows	1,598
NYMEX Strip Prices [Member] | Proved Developed [Member]
Future cash inflows:
Cash inflows	26,468
Future production costs	(9,462)
Future development costs	(58)
Future income tax (none since Savoy is a pass-through entity for income tax purposes)
Future net cash flows	16,948
10% annual discount for estimated timing of cash flows	(3,608)
Standardized measure of discounted future net cash flows	13,340
NYMEX Strip Prices [Member] | Proved Developed [Member] | Oil [Member]
Future cash inflows:
Cash inflows	24,768
NYMEX Strip Prices [Member] | Proved Developed [Member] | Natural Gas Liquids [Member]
Future cash inflows:
Cash inflows	785
NYMEX Strip Prices [Member] | Proved Developed [Member] | Natural Gas [Member]
Future cash inflows:
Cash inflows	915
NYMEX Strip Prices [Member] | Proved Undeveloped (PUDs) [Member]
Future cash inflows:
Cash inflows	13,174
Future production costs	(3,398)
Future development costs	(1,800)
Future income tax (none since Savoy is a pass-through entity for income tax purposes)
Future net cash flows	7,976
10% annual discount for estimated timing of cash flows	(2,336)
Standardized measure of discounted future net cash flows	5,640
NYMEX Strip Prices [Member] | Proved Undeveloped (PUDs) [Member] | Oil [Member]
Future cash inflows:
Cash inflows	12,239
NYMEX Strip Prices [Member] | Proved Undeveloped (PUDs) [Member] | Natural Gas Liquids [Member]
Future cash inflows:
Cash inflows	252
NYMEX Strip Prices [Member] | Proved Undeveloped (PUDs) [Member] | Natural Gas [Member]
Future cash inflows:
Cash inflows	$ 683