Fair Value Measurements (Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation) (Details) (Contingent Consideration Liability, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Contingent Consideration Liability
Contingent consideration for acquisitions
Balance at beginning of period	$ (3,171)	$ (9,317)	$ (7,577)	$ (9,856)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Payments	0	0	3,425	0
Fair value adjustment	1,039	1,038	1,931	1,408
Foreign currency translation adjustment	(127)	(129)	(38)	40
Balance at end of period	$ (2,259)	$ (8,408)	$ (2,259)	$ (8,408)