Bank Loans (Activity In The Allowance For Loan Losses By Portfolio Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 107,668	$ 102,802	$ 112,029	$ 95,579
CECL Adoption				(11,736)
Provision	(4,204)	13,168	(7,631)	32,146
Charge-offs	(4,268)	(150)	(5,202)	(170)
Recoveries		1		2
Ending Balance	99,196	115,821	99,196	115,821
Commercial And Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	56,316	59,962	67,222	69,949
CECL Adoption				(19,940)
Provision	(5,105)	5,691	(15,077)	15,646
Charge-offs	(4,268)	(150)	(5,202)	(152)
Ending Balance	46,943	65,503	46,943	65,503
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	16,665	19,985	16,300	14,253
CECL Adoption				3,499
Provision	4,602	4,058	4,967	6,291
Ending Balance	21,267	24,043	21,267	24,043
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	2,169	2,915	2,015	2,361
CECL Adoption				1,346
Provision	350	(1,108)	504	(1,900)
Ending Balance	2,519	1,807	2,519	1,807
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	13,060	8,165	8,580	3,564
CECL Adoption				791
Provision	(1,157)	2,482	3,323	6,292
Ending Balance	11,903	10,647	11,903	10,647
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	18,873	10,953	17,275	4,613
CECL Adoption				2,674
Provision	(2,920)	2,122	(1,322)	5,788
Ending Balance	15,953	13,075	15,953	13,075
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	341	539	374	442
CECL Adoption				39
Provision	85	(40)	52	17
Recoveries				1
Ending Balance	426	499	426	499
Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	244	283	263	397
CECL Adoption				(145)
Provision	(59)	(37)	(78)	12
Charge-offs				(18)
Recoveries		1		1
Ending Balance	$ 185	$ 247	$ 185	$ 247