Derivatives - Gain (Loss) in the Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Not designated as hedging instrument | Foreign currency forward contract | Other income (expense)
Derivative [Line Items]
Gain (loss) on derivative	$ 2,402	$ 1,143	$ 1,647	$ 3,181