Fair Value Measurement - Rollforward of Unobservable Reconciliations (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31		$ (32,582)
Contingent consideration payments paid in cash			$ 525
Change in fair value of contingent consideration	$ (36,100)	(270)	(37,873)	$ (31,331)
Foreign exchange impact		(3,152)	(4,806)
Balance at December 31	(32,582)	(22,162)	(32,582)
Significant Unobservable Inputs (Level 3)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31		(32,582)	(87,333)
Contingent consideration payments paid in cash			5,769
Contingent consideration payments paid in stock		8,010	9,133
Change in fair value(1)		1,570	37,874
Change in fair value of contingent consideration		270	402
Foreign exchange impact		570	1,573
Balance at December 31	$ (32,582)	$ (22,162)	$ (32,582)	$ (87,333)