Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Loss Contingency Accrual [Roll Forward]
Contingencies accrual, beginning balance	$ 668	$ 1,373
Charges	837	632
Provision used	(450)	(487)
Provision released not used	(391)	(727)
Currency translation adjustments	(10)	(123)
Contingencies accrual, ending balance	654	668
Contingencies accrual, of which current	654
Provision for employee- related litigation
Loss Contingency Accrual [Roll Forward]
Contingencies accrual, beginning balance	236	781
Charges	671	200
Provision used	(402)	(487)
Provision released not used	0	(186)
Currency translation adjustments	(20)	(72)
Contingencies accrual, ending balance	485	236
Contingencies accrual, of which current	485
Provision for tax- related litigation
Loss Contingency Accrual [Roll Forward]
Contingencies accrual, beginning balance	44	592
Charges	0	44
Provision used	0	0
Provision released not used	(44)	(541)
Currency translation adjustments	0	(51)
Contingencies accrual, ending balance	0	44
Contingencies accrual, of which current	0
Other provisions
Loss Contingency Accrual [Roll Forward]
Contingencies accrual, beginning balance	388	0
Charges	166	388
Provision used	(48)	0
Provision released not used	(347)	0
Currency translation adjustments	10	0
Contingencies accrual, ending balance	169	$ 388
Contingencies accrual, of which current	$ 169