Comprehensive Income Accumulated other comprehensive income (loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Accumulated other comprehensive income (loss) [Roll Forward]
Accumulated other comprehensive loss	$ (25,271)		$ (26,348)
Pension liability, net of income tax	462	231
Cash flow hedging gain, net of income tax	(1,561)	(1,046)
Foreign currency transaction adjustments	2,176	3,844
Accumulated Other Comprehensive Loss [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Accumulated other comprehensive loss	(25,271)		(26,348)
Pension liability, net of income tax	462
Cash flow hedging gain, net of income tax	(1,561)
Foreign currency transaction adjustments	2,176
Cash Flow Hedging Gain (Loss) [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Accumulated other comprehensive loss	1,412		2,973
Pension Liability [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Accumulated other comprehensive loss	(30,788)		(31,250)
Cumulative Translation Adjustment [Member]
Accumulated other comprehensive income (loss) [Roll Forward]
Accumulated other comprehensive loss	$ 4,105		$ 1,929