Fair Value Measurements (Details 1) (Fair Value, Inputs, Level 3, USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2014		Dec. 31, 2013
Fair Value, Inputs, Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance of contingent payments	$ 151,848		$ 194,795
Payments	(53,083)		(106,460)
Grants	47,629	[1]	31,608	[1]
Redemption value adjustments	14,819	[2]	38,712	[2]
Transfers (to) from fixed payments	(5,146)		(6,318)
Foreign translation adjustment	925		(489)
Ending Balance of contingent payments	$ 156,992		$ 151,848

[1] Grants are the initial estimated deferred acquisition payments of new acquisitions completed within that fiscal period.

[2] Redemption value adjustments are fair value changes from the Company’s initial estimates of deferred acquisition payments, including the accretion of present value and stock based compensation charges relating to acquisition payments that are tied to continued employment.