Taxation - Income tax uncertainties (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrecognized tax benefits, rollforward
January 1	$ 10,273	$ 5,689	$ 8,743
Changes in tax positions taken during a prior period - increase		3,870
Changes in tax positions taken during a prior period - decrease	(199)		(4,229)
Tax positions taken during the current period - increase	0	0	1,379
Impact of change in foreign currency exchange rates - Increase		714
Impact of change in foreign currency exchange rates - Decrease	(798)		(204)
December 31	9,276	10,273	5,689
Unrecognized tax benefits impacting effective tax rate	$ 0	$ 0	$ 0

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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