Discontinued Operations Discontinued Operations (Details)	12 Months Ended			24 Months Ended
	Dec. 31, 2015 USD ($) mo	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) mo	Jun. 30, 2014 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group Including Discontinued Operation Allowance for Doubtful Accounts					$ 410,000
Business Disposition Contract Sales Price					335,000,000
Escrow Receivable	$ 13,800,000			$ 13,800,000
Proceeds from Divestiture of Businesses, Net of Cash Divested	$ 13,856,000	$ 229,903,000	$ 0	243,759,000
Proceeds from Divestiture of Businesses				143,748,000
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax		69,700,000		$ 74,800,000
Number of Months Receivable Held in Escrow | mo	15			15
Discontinued Operation Transaction Expenses				$ 11,100,000
Transaction Expenses Withheld from Sales Proceeds				5,461,000
Disposal Group Including Discontinued Operation Accumulated Amortization					$ 42,266,000
Proceeds from Divestiture of Business Before Tax Payments		205,400,000		219,180,000
Ecova [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation Transaction Expenses	$ 71,000	$ 9,062,000	$ 0	9,100,000
Indemnification Agreement [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Escrow Receivable	$ 16,800,000			$ 16,800,000
Escrow Percentage of Contract Price	5.00%			5.00%
Working Capital Escrow Adjustment [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Escrow Receivable	$ 1,000,000			$ 1,000,000