Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	$ 18,751	$ 19,325
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	201	627
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	1,839	(1,036)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	20,791	18,916	(95,139)
Net earnings	52,327	46,827	269,493
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 73,118	$ 65,743