Asset Acquisition (Clearfield PPA) (Details) (USD $)			1 Months Ended	3 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Jul. 31, 2013 Clearfield Energy [Member]	Sep. 30, 2012 Clearfield Energy [Member]	Jul. 02, 2012 Clearfield Energy [Member]
Business Acquisition [Line Items]
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual				$ 52,900,000
Purchase Price to Clearfield Energy, Inc.			215,397,000
Assets Acquired:
Current Assets					17,622,000
Assets held for disposition					19,358,000
Property, plant and equipment					91,422,000
Goodwill	153,802,000	152,627,000			153,802,000
Intangibles					37,600,000
Liabilities Assumed:
Current liabilities					(28,274,000)
Liabilities held for disposition					(1,400,000)
Deferred taxes					(65,228,000)
Long term liabilities					$ (9,505,000)