Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended				3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Foreign Currency Translation Adjustment [Member]	Dec. 31, 2011 Foreign Currency Translation Adjustment [Member]	Mar. 31, 2012 Unrealized (Loss) on Net Investment Hedge [Member]	Dec. 31, 2011 Unrealized (Loss) on Net Investment Hedge [Member]	Dec. 31, 2010 Unrealized (Loss) on Net Investment Hedge [Member]	Mar. 31, 2012 Unrealized Actuarial Gain (Loss) Related to Pension Liability [Member]	Dec. 31, 2011 Unrealized Actuarial Gain (Loss) Related to Pension Liability [Member]	Mar. 31, 2012 Unrealized Gain (Loss) on Cash Flow Hedging Instruments [Member]	Dec. 31, 2011 Unrealized Gain (Loss) on Cash Flow Hedging Instruments [Member]	Mar. 31, 2012 Unrealized Gain (Loss) on Post Retirement Obligation [Member]	Dec. 31, 2011 Unrealized Gain (Loss) on Post Retirement Obligation [Member]
Accumulated other comprehensive income (loss)
Beginning balance, accumulated other comprehensive income (loss)	$ 4,436	$ 15,108	$ 5,995	$ 13,992	$ (2,565)	$ (2,565)	$ (2,565)	$ 985	$ 1,189	$ (438)	$ 2,146	$ 459	$ 346
Pre-tax amount	9,821	(9,126)	7,105	(7,613)					(184)	2,688	(1,482)	28	153
Tax benefit	(281)	793							34	(281)	759
Reclassification to net income	(254)	(2,339)	25	(389)				(12)	(55)	(254)	(1,855)	(13)	(40)
Foreign currency translation			(1)	5				21	1	(20)	(6)
Ending balance, accumulated other comprehensive income (loss)	$ 13,722	$ 4,436	$ 13,124	$ 5,995	$ (2,565)	$ (2,565)	$ (2,565)	$ 994	$ 985	$ 1,695	$ (438)	$ 474	$ 459