Goodwill And Intangible Assets (Components Of Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	$ 2,196,597	$ 1,777,015
Intangible assets, accumulated amortization	(470,401)	(421,334)
Customer Relationships [Member]
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	953,739	941,477
Intangible assets, accumulated amortization	(204,261)	(161,797)
Investment Management Agreements [Member]
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	441,000	98,000
Intangible assets, accumulated amortization	0	(14,000)
Broker Relationships [Member]
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	204,367	184,959
Intangible assets, accumulated amortization	(78,559)	(69,677)
Trade Names [Member]
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	193,154	164,335
Intangible assets, accumulated amortization	(62,827)	(59,660)
Technology [Member]
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	109,208	94,712
Intangible assets, accumulated amortization	(47,090)	(44,489)
Agent Relationships [Member]
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	92,000	92,000
Intangible assets, accumulated amortization	(10,175)	(4,042)
Insurance Licenses [Member]
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	74,635	70,385
Intangible assets, accumulated amortization	0	0
Renewal Rights [Domain]
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	21,053	19,514
Intangible assets, accumulated amortization	(18,272)	(17,681)
Other [Member]
Schedule of Indefinite-Lived And Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying amount	107,441	111,633
Intangible assets, accumulated amortization	$ (49,217)	$ (49,988)