Accounting for Derivatives (Details) (Interest rate hedges, USD $)	3 Months Ended		3 Months Ended		6 Months Ended							3 Months Ended	6 Months Ended
	Jun. 30, 2013 Terminated hedge, May 2013	May 31, 2013 Terminated hedge, May 2013	Jun. 30, 2013 Designated as a hedging instrument	Jun. 30, 2012 Designated as a hedging instrument	Jun. 30, 2013 Designated as a hedging instrument	Jun. 30, 2012 Designated as a hedging instrument	Dec. 31, 2012 Designated as a hedging instrument	Jun. 30, 2013 Designated as a hedging instrument Intangible and other assets, net	Jun. 30, 2013 Designated as a hedging instrument Accrued liabilities	Dec. 31, 2012 Designated as a hedging instrument Accrued liabilities	Dec. 31, 2012 Designated as a hedging instrument Other long-term liabilities	Dec. 31, 2010 Terminated hedge, 2010	Jun. 30, 2013 Terminated hedge, 2010
Fair Value Asset (Liability)
Derivatives asset designated as hedging instruments, Fair value								$ 132,000
Derivatives liability designated as hedging instruments, Fair value		(8,800,000)							(3,276,000)	(3,873,000)	(6,043,000)
Total derivatives, Fair value			(3,144,000)		(3,144,000)		(9,916,000)
Pre-tax losses reclassified into interest expense	600,000												1,000,000
Amount of interest rate swap termination payments												43,000,000
Notional amount of interest rate swaps		250,000,000	250,000,000		250,000,000							585,000,000
Weighted average effective fixed interest rate on interest rate swaps (as a percent)			1.70%		1.70%							4.60%
Interest income recorded due to ineffectiveness related to interest rate swaps			200,000	0	200,000	0
Deferred pre-tax loss to be reclassified during next 12 months	$ 3,800,000		$ 3,300,000		$ 3,300,000								$ 1,100,000