Fair Value Measurements (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Net valuation of the Company's derivatives subject to fair value measurement on a recurring basis
Estimated fair value of the Notes	$ 151,500,000	$ 151,500,000
Book value of notes	150,000,000	150,000,000
Level 1 [Member]
Net valuation of the Company's derivatives subject to fair value measurement on a recurring basis
Commodity Derivatives:
Level 2 [Member]
Net valuation of the Company's derivatives subject to fair value measurement on a recurring basis
Commodity Derivatives:	4,439,000	6,418,000
Level 3 [Member]
Net valuation of the Company's derivatives subject to fair value measurement on a recurring basis
Commodity Derivatives: