Bank Loans (Activity In The Allowance For Loan Losses By Portfolio Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 95,579	$ 85,833
CECL Adoption	(11,736)
Provision	28,264	9,977
Charge-offs	(193)	(386)
Recoveries	115	155
Ending Balance	112,029	95,579
Commercial And Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	69,949	68,367
CECL Adoption	(19,940)
Provision	17,341	1,821
Charge-offs	(153)	(239)
Recoveries	25
Ending Balance	67,222	69,949
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	14,253	11,228
CECL Adoption	3,499
Provision	(1,452)	2,974
Charge-offs		(41)
Recoveries		92
Ending Balance	16,300	14,253
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	2,361	1,978
CECL Adoption	1,346
Provision	(1,692)	383
Ending Balance	2,015	2,361
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	3,564	1,778
CECL Adoption	791
Provision	4,225	1,786
Ending Balance	8,580	3,564
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	4,613	1,241
CECL Adoption	2,674
Provision	9,988	3,372
Ending Balance	17,275	4,613
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	442	310
CECL Adoption	39
Provision	(195)	129
Recoveries	88	3
Ending Balance	374	442
Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	397	931
CECL Adoption	(145)
Provision	49	(488)
Charge-offs	(40)	(106)
Recoveries	2	60
Ending Balance	$ 263	$ 397