Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Income Taxes
Effective income tax rates (as a percent)	27.60%	21.30%	27.50%	23.40%
One-time tax cost included in provision for taxes	$ 6,600
Gain for the adjustment of a contingent acquisition related to purchase price obligation	17,813
Reduction in tax expense primarily to reserve adjustments from the favorable settlement of certain international tax positions		10,300
Minimum number of tax jurisdictions			50
Liability for unrecognized tax benefits, including penalties and interest, which if recognized would impact the effective tax rate	24,646		24,646
Unrecognized tax benefits, anticipated adjustment for changing facts and circumstances, over the next twelve month period	$ 4,600		$ 4,600