Goodwill And Intangible Assets (Schedule Of Intangible Assets Subject To Amortization) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Historical Cost	$ 1,270,409	$ 1,064,002
Accumulated Amortization	(697,188)	(569,219)
Net	573,221	494,783
Trade Names [Member]
Historical Cost	192,396	181,231
Accumulated Amortization	(77,842)	(65,722)
Net	$ 114,554	$ 115,509
Finite-Lived Intangible Asset, Useful Life	10 years 3 months 18 days	10 years 10 months 24 days
Patents And Patent Licenses [Member]
Historical Cost	$ 67,903	$ 67,887
Accumulated Amortization	(62,513)	(60,541)
Net	$ 5,390	$ 7,346
Finite-Lived Intangible Asset, Useful Life	6 years 6 months	6 years 6 months
Customer Relationships [Member]
Historical Cost	$ 623,966	$ 507,330
Accumulated Amortization	(366,706)	(316,122)
Net	$ 257,260	$ 191,208
Finite-Lived Intangible Asset, Useful Life	8 years 6 months	9 years 1 month 6 days
Other Purchased Intangibles [Member]
Historical Cost	$ 386,144	$ 307,554
Accumulated Amortization	(190,127)	(126,834)
Net	$ 196,017	$ 180,720
Finite-Lived Intangible Asset, Useful Life	4 years 6 months	4 years 4 months 24 days
2019 Business Acquisitions [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 212,330
2019 Business Acquisitions [Member] | Trade Names [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 10,450
Weighted-Average Amortization Period, years	8 years 1 month 6 days
2019 Business Acquisitions [Member] | Customer Relationships [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 121,803
Weighted-Average Amortization Period, years	7 years 2 months 12 days
2019 Business Acquisitions [Member] | Trademarks [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 32,540
Weighted-Average Amortization Period, years	6 years 2 months 12 days
2019 Business Acquisitions [Member] | Other Purchased Intangibles [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 47,537
Weighted-Average Amortization Period, years	3 years 8 months 12 days