Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Income Taxes [Abstract]
U.S. federal tax rate	35.00%	35.00%	35.00%
Excess tax benefits	$ 13,700,000	$ 10,700,000	$ 0
Cumulative undistributed earnings of non-U.S. subsidiaries	263,800,000	197,900,000	139,500,000
Valuation allowance for deferred tax assets	1,700,000	1,800,000
Net change in the total valuation allowance	100,000	100,000
Net operating loss carryforwards for state income tax purposes	58,700,000
Net operating loss carryforwards for foreign income tax purposes	1,900,000
End year net operating loss carryforwards offset future taxable income	2023
Accrued interest and penalties related to the unrecognized tax benefits	900,000	500,000
Total unrecognized tax benefits	4,994,000	3,912,000	3,601,000	3,601,000
Unrecognized tax benefits that would affect effective tax rate	$ 4,300,000