Commitments and contingencies - Contingencies (Details) $ in Thousands	6 Months Ended
Jun. 30, 2020 USD ($)
Loss Contingency Accrual [Roll Forward]
Contingencies accrual, beginning balance	$ 6,385
Increase	91
Provision used	(446)
Provision released not used	(1,770)
Currency translation adjustments	(134)
Contingencies accrual, ending balance	4,126
Contingencies accrual, of which current	4,126
Provision for employee-related litigation
Loss Contingency Accrual [Roll Forward]
Contingencies accrual, beginning balance	620
Increase	91
Provision used	(4)
Provision released not used	0
Currency translation adjustments	1
Contingencies accrual, ending balance	708
Contingencies accrual, of which current	708
Other provisions
Loss Contingency Accrual [Roll Forward]
Contingencies accrual, beginning balance	5,765
Increase	0
Provision used	(442)
Provision released not used	(1,770)
Currency translation adjustments	(135)
Contingencies accrual, ending balance	3,418
Contingencies accrual, of which current	$ 3,418

Loss Contingency Accrual, Foreign Currency Translation Gain (Loss)

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- Definition

Loss Contingency Accrual, Provision Released Not Used

+ References

No definition available.

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- Definition

Loss Contingency Accrual, Provision Used

+ References

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- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

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- Definition

Amount of loss contingency liability expected to be resolved within one year or the normal operating cycle, if longer.

+ References

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- Definition

Amount charged against operating income increasing loss contingency liability, after adjustments to reduce previously estimated charges.

+ References

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- Definition

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

+ References

No definition available.

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