Accumulated Other Comprehensive Loss (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Rollforward of Accumulated other comprehensive income (loss)
Beginning balance	$ (104,632)		$ (114,054)
Other comprehensive income (loss) before reclassifications, net of tax	(2,702)		6,720
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(382)		(382)
Total other comprehensive income, net	(3,084)	1,863	6,338	4,120
Ending balance	(107,716)		(107,716)
Gains (losses) on derivatives designated as hedging instruments | Interest rate derivatives
Rollforward of Accumulated other comprehensive income (loss)
Beginning balance	766
Other comprehensive income (loss) before reclassifications, net of tax	(220)		409
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	135		272
Total other comprehensive income, net	(85)		681
Ending balance	681		681
Gains (losses) on derivatives designated as hedging instruments | Foreign currency derivatives
Rollforward of Accumulated other comprehensive income (loss)
Beginning balance	6,690
Other comprehensive income (loss) before reclassifications, net of tax	(2,482)		6,311
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(1,898)		(4,001)
Total other comprehensive income, net	(4,380)		2,310
Ending balance	2,310		2,310
Defined Benefit Pension Items
Rollforward of Accumulated other comprehensive income (loss)
Beginning balance	(112,088)		(114,054)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1,381		3,347
Total other comprehensive income, net	1,381		3,347
Ending balance	$ (110,707)		$ (110,707)