Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income		$ 67,659	$ 56,726	$ 48,888
Other comprehensive income/(loss):
Unrealized gain/(loss) on cash flow hedges		8,773	(13,919)	19,802
Foreign currency translation (loss)/gain		(3,486)	(25,700)	18,894
Retirement benefits		(2,539)	382	1,273
Reclassification adjustments
Gain on cash flow hedges	[1]	(3,951)
Gain on cash flow hedges	[1]		(3,149)	(6,899)
Retirement benefits	[2]	(159)	(153)	256
Income tax (expense)/benefit relating to above	[3]	(63)	4,782	(3,979)
Total other comprehensive (loss)/income		(1,425)	(37,757)	29,347
Total comprehensive income		$ 66,234	$ 18,969	$ 78,235

[1] These are reclassified to net income and are included either in cost of revenues or operating expenses, as applicable in the consolidated statements of income. Refer to Note 17 to the consolidated financial statements.

[2] These are reclassified to net income and are included in other income, net in the consolidated statements of income. Refer to Note 20 to the consolidated financial statements.

[3] These are income tax (expense)/benefit recognized on cash flow hedges and retirement benefits. Refer to Note 22 to the consolidated financial statements.