Sale of Appalachian Gathering Assets (Details) - USD ($) $ in Thousands		12 Months Ended
	Mar. 31, 2012	Dec. 31, 2014
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Gain on sale of gathering system		$ 40,000
Appalachian Gathering Assets
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Gain on sale of gathering system		$ 40,000
Period for which entity is committed to deliver minimum annual volumes into gathering systems, with certain carryback and carryforward adjustments for overages or deficiencies	7 years
Period of exclusive rights to gather the gas within AOD	20 years