Fair Value Measurements Changes in Fair Value Level 3 (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Roll forward of acquisition-related contingent consideration payable [Roll Forward]
Fair value of contingent consideration payable	$ 17,738
Contingent consideration, fair market value of additions during the year	4,653
Payments of contingent consideration	(6,550)	0	0
Charge from change in fair value of estimated contingent consideration payable	1,275
Contingent consideration, translation adjustment	169
Fair value of contingent consideration payable	$ 17,285	$ 17,738