Asset Retirement Obligation - Asset Retirement Obligation Summary (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012
Asset Retirement Obligation Disclosure [Abstract]
Oil and gas producing properties - asset retirement obligation liability	$ 2	[1]		$ 4
Estimated well life	27 years 6 months		15 years

[1] This is a Level 3 fair value measurement.