Discontinued Operations Discontinued Operations (Details) - USD ($) $ in Thousands	12 Months Ended			24 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Jun. 30, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Business Disposition Contract Sales Price					$ 335,000
Proceeds from Divestiture of Businesses, Net of Cash Divested	$ 0	$ 13,856	$ 229,903
Proceeds from Divestiture of Businesses				$ 143,700
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			69,700	74,800
Discontinued Operation Transaction Expenses				11,100
Transaction Expenses Withheld from Sales Proceeds				5,500
Ecova [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation Transaction Expenses		$ 71	$ 9,062	$ 9,100