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Debt And Liquidity (Narrative) (Details)			6 Months Ended
	Feb. 27, 2015 USD ($)	Nov. 30, 2010 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Nov. 20, 2012 USD ($)
Debt Instrument [Line Items]
Fair value of debt			$ 520,400,000	$ 473,300,000
Book value of debt			$ 548,600,000	$ 529,700,000
Stated interest rate				6.375%
Interest rate used to record at present value			7.00%
Loan balance, net of unamortized discount			$ 199,215,000	$ 188,104,000
Senior Notes
Debt Instrument [Line Items]
Principal amount issued					$ 300,000,000
Stated interest rate					6.375%
Redemption price, percentage of principal, prior to November 15, 2016					100.00%
Redemption price, percentage of principal, prior to November 15, 2015					106.375%
Repurchase price, percentage of principal, due to change in control					101.00%
Senior Notes | Minimum
Debt Instrument [Line Items]
Unpaid indebtedness or accelerated proceeds exceeds			50,000,000
Unpaid judgment or decree in excess of			50,000,000
Senior Notes | Maximum
Debt Instrument [Line Items]
Percentage of principal allowed to redeem					35.00%
Senior Subordinated Notes
Debt Instrument [Line Items]
Face amount of debt issued in connection with acquisition		$ 200,000,000
Interest rate used to record at present value		7.00%
Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Unused borrowing capacity			258,000,000
Outstanding letters of credit			$ 6,300,000
Minimum cash interest coverage ratio	2.50
Range of maximum senior secured leverage ratio, minimum	3.75
Range of maximum senior secured leverage ratio, maximum	3.00
Amended and Restated Credit Agreement | Minimum
Debt Instrument [Line Items]
Undrawn commitment fee	0.35%
Amended and Restated Credit Agreement | Maximum
Debt Instrument [Line Items]
Undrawn commitment fee	0.50%
Amended and Restated Credit Agreement | LIBOR | Minimum
Debt Instrument [Line Items]
Margin spread on variable interest rate	2.25%
Amended and Restated Credit Agreement | LIBOR | Maximum
Debt Instrument [Line Items]
Margin spread on variable interest rate	3.75%
Term Loan Facility | Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Borrowing capacity	$ 40,000,000
Revolving Credit Facility | Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Borrowing capacity	$ 400,000,000

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