Bank Loans (Activity In The Allowance For Loan Losses By Portfolio Segment) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 102,802	$ 88,172	$ 95,579	$ 85,833
CECL Adoption			(11,736)
Provision	13,168	2,353	32,146	4,636
Charge-offs	(150)	(54)	(170)	(110)
Recoveries	1	1	2	113
Ending Balance	115,821	90,472	115,821	90,472
Commercial And Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	59,962	68,566	69,949	68,367
CECL Adoption			(19,940)
Provision	5,691	743	15,646	954
Charge-offs	(150)	(46)	(152)	(58)
Ending Balance	65,503	69,263	65,503	69,263
Residential Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	19,985	11,585	14,253	11,228
CECL Adoption			3,499
Provision	4,058	457	6,291	727
Recoveries				87
Ending Balance	24,043	12,042	24,043	12,042
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	2,915	2,227	2,361	1,978
CECL Adoption			1,346
Provision	(1,108)	84	(1,900)	333
Ending Balance	1,807	2,311	1,807	2,311
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	8,165	2,421	3,564	1,778
CECL Adoption			791
Provision	2,482	57	6,292	700
Ending Balance	10,647	2,478	10,647	2,478
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	10,953	1,724	4,613	1,241
CECL Adoption			2,674
Provision	2,122	678	5,788	1,161
Ending Balance	13,075	2,402	13,075	2,402
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	539	372	442	310
CECL Adoption			39
Provision	(40)	49	17	110
Recoveries			1	1
Ending Balance	499	421	499	421
Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	283	146	194	88
CECL Adoption			58
Provision	(37)	40	12	118
Charge-offs		(8)	(18)	(52)
Recoveries	1	1	1	25
Ending Balance	$ 247	179	247	179
Unallocated [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance		1,131	203	843
CECL Adoption			$ (203)
Provision		245		533
Ending Balance		$ 1,376		$ 1,376

Loans and leases receivable allowance impact of current expected credit loss adoption.

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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