Property and Equipment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property and equipment	$ 603,714	$ 603,239
Oil and Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	564,755	565,406
Equipment and Other [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	17,237	19,052
Equipment and Other [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Equipment and Other [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	39 years
Drilling Rig [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Property and equipment	$ 21,722	$ 18,781