Financial Derivative Instruments - Impact of Cash Flow Hedges (Details) - Cash Flow Hedging - Foreign currency derivatives - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Gains (losses) for designated hedge contracts
(Gain) loss recognized in AOCI on derivatives	$ 3,440	$ 3,083	$ 1,869	$ (23)
(Gain) loss reclassified from AOCI into income	$ (3,538)	$ (1,749)	$ (7,438)	$ (3,336)