Fair Value Measurements (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Net valuation of the Company's derivatives subject to fair value measurement on a recurring basis
Estimated fair value of the Notes	$ 296,000,000	$ 301,000,000
Book value of notes	350,000,000	350,000,000
Quoted Prices in Active Markets (Level 1)
Net valuation of the Company's derivatives subject to fair value measurement on a recurring basis
Commodity derivatives at fair value	0	0
Significant Other Observable Inputs (Level 2)
Net valuation of the Company's derivatives subject to fair value measurement on a recurring basis
Commodity derivatives at fair value	11,175,000	8,631,000
Significant Unobservable Inputs (Level 3)
Net valuation of the Company's derivatives subject to fair value measurement on a recurring basis
Commodity derivatives at fair value	$ 0	$ 0