Fair Value Measurements Reconciliation of Fair Value Measurements of Liability for Future Consideration Payments (Details) (Acquisition-related Future Consideration Liabilities [Member], Fair Value, Inputs, Level 3 [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Acquisition-related Future Consideration Liabilities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 11,759		$ 13,404		$ 20,058
New acquisition adjustment	330	[1]	3,361	[1]	(2,600)	[1]
Changes in fair value	(941)	[2]	(793)	[2]	900	[2]
Contingent consideration payments	(4,659)		(4,213)		(4,954)
Ending balance	$ 6,489		$ 11,759		$ 13,404

[1] Amounts include the preliminary fair value estimate of the contingent payment liability recorded in connection with a new acquisition or the revision thereof upon finalization of the valuation process related to initial purchase accounting.

[2] Amounts were primarily included as a (decrease) increase to Intangible asset related expense on the Consolidated Statements of Income.