Acquisitions, Goodwill And Other Intangible Assets (Schedule Of Other Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Acquired Intangible Assets
Finite-Lived Intangible Assets, Accumulated Amortization	$ 95,936	$ 77,362	$ 90,658
Intangible Assets, Gross (Excluding Goodwill)	276,627	191,673	220,790
Intangible Assets, Net (Excluding Goodwill)	180,691	114,311	130,132
Customer Relationships
Acquired Intangible Assets
Finite-Lived Intangible Assets, Gross	187,229	113,513	138,687
Finite-Lived Intangible Assets, Accumulated Amortization	45,393	34,704	42,276
Finite-Lived Intangible Assets, Net	$ 141,836	$ 78,809	96,411
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	$ 59,415	$ 57,347	57,576
Finite-Lived Intangible Assets, Accumulated Amortization	40,130	34,850	38,764
Finite-Lived Intangible Assets, Net	$ 19,285	$ 22,497	18,812
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	$ 14,833	$ 9,741	10,995
Finite-Lived Intangible Assets, Accumulated Amortization	5,607	4,494	5,381
Finite-Lived Intangible Assets, Net	$ 9,226	$ 5,247	5,614
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	$ 10,154	$ 6,076	8,536
Finite-Lived Intangible Assets, Accumulated Amortization	4,689	3,230	4,128
Finite-Lived Intangible Assets, Net	$ 5,465	$ 2,846	4,408
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	309
Finite-Lived Intangible Assets, Accumulated Amortization	117	84	109
Finite-Lived Intangible Assets, Net	$ 192	$ 225	200
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	$ 4,687