Fair Value Measurement - Rollforward of Unobservable Reconciliations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31	$ 22,162,000
Change in fair value of contingent consideration	10,417,000	$ (270,000)	$ (37,873,000)
Foreign exchange impact	(3,557,000)	(3,152,000)
Balance at December 31	19,283,000	22,162,000
Significant Unobservable Inputs (Level 3)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31	22,162,000	32,582,000
Contingent consideration payments paid in stock	(11,374,000)	(8,010,000)
Change in fair value(1)	(2,012,000)	(1,570,000)
Change in fair value of contingent consideration	402,499	0
Foreign exchange impact	(312,000)	(570,000)
Balance at December 31	$ 19,283,000	$ 22,162,000	$ 32,582,000