Goodwill And Other Intangible Assets (Fair Values Of Intangible Assets Acquired In Various Business Combinations By Class) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule of Acquired Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, gross carrying amount	$ 554,097	$ 556,491
Finite-lived intangible assets, accumulated amortization	(276,591)	(238,596)
Intangible assets, net (excluding goodwill)	277,506	317,895
Customer relationships [Member]
Schedule of Acquired Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, gross carrying amount	287,116	286,951
Finite-lived intangible assets, accumulated amortization	(138,635)	(118,031)
Marketing assets [Member]
Schedule of Acquired Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, gross carrying amount	34,642	34,246
Finite-lived intangible assets, accumulated amortization	(5,918)	(3,648)
Acquired software and technology [Member]
Schedule of Acquired Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, gross carrying amount	232,339	233,094
Finite-lived intangible assets, accumulated amortization	(132,038)	(115,048)
Non-compete agreements [Member]
Schedule of Acquired Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, gross carrying amount	0	2,200
Finite-lived intangible assets, accumulated amortization	$ 0	$ (1,869)