Discontinued Operations Summary of Income Statement Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended	21 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Sep. 30, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax						$ 70,200
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ 289	$ (55)	$ 485	$ 70,585
Transaction expenses withheld from proceeds					$ (5,400)
Revenues	0	0	0	87,534
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	547	0	710	161,100
Transaction expenses and accelerated employee benefits (2)					11,000
Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Taxes Net of Transaction Costs	523	(86)	686	152,038
Income (loss) before income taxes	523	(86)	686	156,513
Income tax expense (benefit)	234	(31)	201	85,741
Net income (loss) from discontinued operations	289	(55)	485	70,772
Net income attributable to noncontrolling interests	(32)	(20)	(73)	(213)
Ecova [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transaction expenses and accelerated employee benefits (2)	24	86	24	9,062	$ 9,100
Net income attributable to noncontrolling interests	$ 0	$ 0	$ 0	$ (187)