Discontinued Operations Discontinued Operations Summary of Cash Proceeds from Sale of Discontinued Operations (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Business Disposition Contract Sales Price	$ 335,000
Business Dispositions Tax Payments Made	(74,842)
Business Disposition Estimated Tax Payments	(172)
Business Disposition Contract Price Closing Adjustments	3,914
Business Disposition Adjusted Contract Price	338,914
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents	(95,932)			(95,932)
Disposal Group Including Discontinued Operation Escrow Receivable	13,079
Proceeds from Divestiture of Business Before Tax Payments	205,395
Proceeds from Divestiture of Businesses, Net of Cash Divested	229,903	0	0
Repayment of borrowings from Ecova line of credit	(46,000)	(11,000)	(14,000)
Payments for Repurchase of Redeemable Noncontrolling Interest	20,871	0	0
Payments to Noncontrolling Interests	(54,179)	0	0
Transaction Expenses Withheld from Sales Proceeds	(5,390)
Proceeds from Divestiture of Businesses	143,460
Ecova [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Repayment of borrowings from Ecova line of credit	$ (40,000)