Goodwill and Other Intangible Assets (Schedule of intangible assets subject to amortization) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-lived Intangible Assets [Roll Forward]
Intangible assets subject to amortization, beginning balance	$ 254,430	$ 247,559
Intangible assets acquired during the year	2,092	47,368
Amortization during the year	(27,613)	(30,745)	$ (34,279)
Currency translation during the year	(2,762)	(9,752)
Intangible assets subject to amortization, ending balance	226,147	254,430	247,559
Customer relationships
Finite-lived Intangible Assets [Roll Forward]
Intangible assets subject to amortization, beginning balance	244,628	234,835
Intangible assets acquired during the year	2,092	47,361
Amortization during the year	(25,527)	(28,389)
Currency translation during the year	(2,752)	(9,179)
Intangible assets subject to amortization, ending balance	218,441	244,628	234,835
Patents
Finite-lived Intangible Assets [Roll Forward]
Intangible assets subject to amortization, beginning balance	4,495	7,061
Intangible assets acquired during the year	0	0
Amortization during the year	(2,156)	(2,272)
Currency translation during the year	(111)	(294)
Intangible assets subject to amortization, ending balance	2,228	4,495	7,061
Other
Finite-lived Intangible Assets [Roll Forward]
Intangible assets subject to amortization, beginning balance	5,307	5,663
Intangible assets acquired during the year	0	7
Amortization during the year	70	(84)
Currency translation during the year	101	(279)
Intangible assets subject to amortization, ending balance	$ 5,478	$ 5,307	$ 5,663