Derivative Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended														12 Months Ended								12 Months Ended							12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Open costless collar contracts [Member] Oil contract 1 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil contract 2 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil contract 3 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil contract 4 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil contract 5 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil contract 6 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil contract 7 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas contract 1 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas contract 2 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas contract 3 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas contract 4 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas contract 5 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas contract 6 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil [Member] Oil contract 1 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil [Member] Oil contract 2 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil [Member] Oil contract 3 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil [Member] Oil contract 4 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil [Member] Oil contract 5 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil [Member] Oil contract 6 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Oil [Member] Oil contract 7 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas [Member] Natural Gas contract 1 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas [Member] Natural Gas contract 2 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas [Member] Natural Gas contract 3 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas [Member] Natural Gas contract 4 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas [Member] Natural Gas contract 5 [Member]	Dec. 31, 2012 Open costless collar contracts [Member] Natural Gas [Member] Natural Gas contract 6 [Member]	Dec. 31, 2012 Open Swap Contracts [Member] Oil [Member]	Dec. 31, 2012 Open Swap Contracts [Member] Oil [Member] Open Swap Contracts for Oil One [Member]	Dec. 31, 2012 Open Swap Contracts [Member] Oil [Member] Open Swap Contracts for Oil Two [Member]
Summary of contracts for oil and natural gas
Calculation Period			07/01/2013 - 12/31/2013	01/01/2014 - 12/31/2014	01/01/2014 - 12/31/2014	01/01/2014 - 12/31/2014	01/01/2014 - 12/31/2014	01/01/2014 - 12/31/2014	01/01/2014 - 12/31/2014	04/01/2013 - 12/31/2013	04/01/2013 - 12/31/2013	04/01/2013 - 12/31/2013	07/01/2013 - 12/31/2013	01/01/2014 - 12/31/2014	01/01/2014 - 12/31/2014		01-01-2013 - 03-31-2013	01-01-2013 - 12-31-2013	01-01-2013 - 12-31-2013	01-01-2013 -12-31-2013	01-01-2013 - 12-31-2013	01-01-2013 -06-30-2014	01-01-2013 - 06-30-2014		01-01-2013 - 07-31-2013	01-01-2013 - 12-31-2013	01-01-2013 - 12-31-2013	01-01-2013 - 12-31-2013	01-01-2014 - 12-31-2014	01-01-2014 - 12-31-2014		01-01-2013 - 12-31-2013	01-01-2013 - 12-31-2013
Notional Quantity			20,000	15,000	30,000	15,000	20,000	15,000	15,000	100,000	100,000	100,000	150,000	100,000	150,000		20,000	20,000	20,000	20,000	20,000	8,000	12,000		150,000	100,000	100,000	100,000	100,000	100,000		10,000	10,000
Price Floor			90.00	85.00	85.00	87.00	90.00	90.00	90.00	3.25	3.25	3.50	3.00	3.00	3.25		90.00	85.00	90.00	85.00	85.00	90.00	90.00		4.50	3.00	3.00	3.00	3.25	3.25		90.20	90.65
Price Ceiling			103	97.50	98.00	97.00	97.00	97.90	98.00	4.41	4.44	4.37	4.24	5.15	5.21		110	102	115	110	109	114	116		5.75	3.83	4.95	4.96	5.37	5.42
Fair Value of Asset (Liability)	$ 4,479	$ 9,282														$ 3,789	$ 122	$ 96	$ 980	$ 471	$ 418	$ 666	$ 1,036	$ 1,135	$ 1,154	$ (146)	$ 40	$ 41	$ 19	$ 27	$ (670)	$ (362)	$ (308)