Restructuring Activities (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) Position	Sep. 30, 2017 USD ($)
Restructuring Activities [Abstract]
Restructuring and Related Cost, Expected Number of Positions Eliminated | Position			40
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Expected Cost, Total	$ 2,069		$ 2,069
Restructuring and Related Cost, Cost Incurred to Date	1,910		1,910
Restructuring and Related Cost, Expected Cost Remaining	159		159
Restructuring charges	70	$ 0	1,177	$ 45
Cumulative translation adjustment			1,600
Tax benefit			1,000
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance			498
Accruals			1,177
Payments			(1,505)
Currency translation and other adjustments			60
Restructuring Reserve, Ending Balance	230		230
Employee Termination Benefits [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Expected Cost, Total	824		824
Restructuring and Related Cost, Cost Incurred to Date	824		824
Restructuring and Related Cost, Expected Cost Remaining	0		0
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance			465
Accruals			359
Payments			(632)
Currency translation and other adjustments			(11)
Restructuring Reserve, Ending Balance	181		181
Lease Termination Costs [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Expected Cost, Total	591		591
Restructuring and Related Cost, Cost Incurred to Date	591		591
Restructuring and Related Cost, Expected Cost Remaining	0		0
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance			0
Accruals			591
Payments			(613)
Currency translation and other adjustments			71
Restructuring Reserve, Ending Balance	49		49
Assets Write-offs/Impairment [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Expected Cost, Total	222		222
Restructuring and Related Cost, Cost Incurred to Date	222		222
Restructuring and Related Cost, Expected Cost Remaining	0		0
Other Restructuring Costs [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Expected Cost, Total	432		432
Restructuring and Related Cost, Cost Incurred to Date	273		273
Restructuring and Related Cost, Expected Cost Remaining	159		159
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance			33
Accruals			227
Payments			(260)
Currency translation and other adjustments			0
Restructuring Reserve, Ending Balance	$ 0		$ 0