Fair Value Measurements - Estimated Fair Value of Liabilities Measured on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Details) - Contingent Consideration Liabilities [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement at beginning of period		$ 644
Contingent consideration liability recorded upon acquisition	$ 61,242	431
Change in fair value measurement	7,265
Changes resulting from foreign currency fluctuations	126	(36)
Contingent consideration paid or settled	(1,132)	$ (1,039)
Fair value measurement at end of period	$ 67,501