Other Non-Current liabilities - Summary of Other Non-Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Liabilities, Noncurrent [Abstract]
Retirement benefits	$ 9,604	$ 8,940
Contingent consideration	9,000	0
Derivative instruments	1,785	29
Deferred transition revenue	995	924
Unrecognized tax benefits	1,068	907
Finance lease liabilities	229	281
Accrued capital expenditures	0	3,486
Others	120	3,568
Other non-current liabilities	$ 22,801	$ 18,135
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other non-current liabilities	Other non-current liabilities