Acquisitions, Goodwill And Other Intangible Assets (Schedule Of Other Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Acquired Intangible Assets
Finite-Lived Intangible Assets, Accumulated Amortization	$ 77,362	$ 75,198
Intangible Assets, Gross (Excluding Goodwill)	191,673	188,141
Intangible Assets, Net (Excluding Goodwill)	114,311	112,943	$ 109,347
Customer Relationships
Acquired Intangible Assets
Finite-Lived Intangible Assets, Gross	113,513	110,784
Finite-Lived Intangible Assets, Accumulated Amortization	34,704	32,414
Finite-Lived Intangible Assets, Net	$ 78,809	$ 78,370
Customer Relationships | Minimum
Acquired Intangible Assets
Estimated useful life in years	6 years	6 years
Customer Relationships | Maximum
Acquired Intangible Assets
Estimated useful life in years	16 years	16 years
Patents
Acquired Intangible Assets
Finite-Lived Intangible Assets, Gross	$ 57,347	$ 56,468
Finite-Lived Intangible Assets, Accumulated Amortization	34,850	34,066
Finite-Lived Intangible Assets, Net	$ 22,497	$ 22,402
Patents | Minimum
Acquired Intangible Assets
Estimated useful life in years	3 years	3 years
Patents | Maximum
Acquired Intangible Assets
Estimated useful life in years	19 years	19 years
Tradenames
Acquired Intangible Assets
Finite-Lived Intangible Assets, Gross	$ 9,741	$ 10,041
Finite-Lived Intangible Assets, Accumulated Amortization	4,494	5,667
Finite-Lived Intangible Assets, Net	$ 5,247	$ 4,374
Tradenames | Minimum
Acquired Intangible Assets
Estimated useful life in years	3 years	3 years
Tradenames | Maximum
Acquired Intangible Assets
Estimated useful life in years	15 years	15 years
Non-compete Agreements
Acquired Intangible Assets
Finite-Lived Intangible Assets, Gross	$ 6,076	$ 5,852
Finite-Lived Intangible Assets, Accumulated Amortization	3,230	2,975
Finite-Lived Intangible Assets, Net	$ 2,846	$ 2,877
Non-compete Agreements | Minimum
Acquired Intangible Assets
Estimated useful life in years	3 years	3 years
Non-compete Agreements | Maximum
Acquired Intangible Assets
Estimated useful life in years	6 years	6 years
Other
Acquired Intangible Assets
Finite-Lived Intangible Assets, Gross	$ 309	$ 309
Finite-Lived Intangible Assets, Accumulated Amortization	84	76
Finite-Lived Intangible Assets, Net	$ 225	$ 233
Other | Minimum
Acquired Intangible Assets
Estimated useful life in years	2 years	2 years
Other | Maximum
Acquired Intangible Assets
Estimated useful life in years	12 years	12 years
Purchased research and development
Acquired Intangible Assets
Indefinite-Lived Intangible Assets - Purchased research and development	$ 4,687	$ 4,687