Fair Value Measurements Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Preferred, Fair Value Adjustment	$ (498)	$ 1,137	$ (1,344)	$ 4,340
Net gains associated with foreign currency derivatives	(600)	100	100	1,200
Fair Value Adjustment Of Warrants, Income Statement	(179)	$ (47)	22	(11,568)
Business Combination, Contingent Consideration, Liability	11,300		11,300
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ (600)		$ 3,700	$ 0