Income Taxes - Recognized in Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Unrealized gain/(loss) on cash flow hedges		$ (2,702)	$ (113)	$ 2,106	$ (1,656)
Retirement benefits		257	19	248	(90)
Currency translation adjustments		(4,204)	(413)	(4,204)	(1,119)
Total income tax expense recognized in other comprehensive income	[1]	$ (6,649)	$ (507)	$ (1,850)	$ (2,865)

[1] These are income tax (expense)/benefit recognized on cash flow hedges, retirement benefits and foreign currency translation gains/(losses). Refer to Note 21 - Income Taxes to the unaudited consolidated financial statements.