Derivatives and Hedge Accounting - Summary of Effect of Foreign Currency Exchange Contracts (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Effect of net investment hedges on accumulated other comprehensive loss	$ 0	$ 0	$ (580)	$ 0
Gain/(Loss) recognized in unaudited consolidated statements of income	1,009	1,385	3,471	3,414
Foreign currency exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Effect of net investment hedges on accumulated other comprehensive loss	0	0	(580)	0
Derivatives in cash flow hedging relationships | Derivatives in hedging relationships | Foreign currency exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Effect of net investment hedges on accumulated other comprehensive loss	(3,596)	(11,944)	5,629	(29,187)
Reclassification out of Accumulated Other Comprehensive Income | Derivatives not designated as hedging instruments | Foreign currency exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) recognized in unaudited consolidated statements of income	$ (794)	$ (4,268)	$ 3,525	$ (9,837)