Fair Value Measurement (Reconciliation of Level 3 Liabilities) (Details) (Level 3, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Level 3
Reconciliation of beginning and ending Level 3 financial liability balance
Beginning balance	$ 20,907	$ 3,015	$ 2,977
Earnouts related to acquisition	4,288	17,733	2,581
Payment of contingent purchase obligation	2,407	284	3,212
Adjustment to contingent purchase obligation	(5,734)	443	669
Ending balance	$ 17,054	$ 20,907	$ 3,015