Bank Loans (Recorded Balances Of Loans and Amount Of Allowance Allocated Based Upon Impairment Method by Portfolio Segment) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	$ 8,182	$ 8,182
Allowance for Loan Losses, Collectively Evaluated for Impairment	103,847	87,397
Allowance for Loan Losses, Total	112,029	95,579	$ 85,833
Recorded Investment in Loans, Individually Evaluated for Impairment	13,802	14,587
Recorded Investment in Loans, Collectively Evaluated for Impairment	11,157,011	9,738,029
Recorded Investment in Loans, Total	11,170,813	9,752,616
Commercial And Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	8,158	8,158
Allowance for Loan Losses, Collectively Evaluated for Impairment	59,064	61,791
Allowance for Loan Losses, Total	67,222	69,949	68,367
Recorded Investment in Loans, Individually Evaluated for Impairment	12,251	12,991
Recorded Investment in Loans, Collectively Evaluated for Impairment	4,283,838	3,425,962
Recorded Investment in Loans, Total	4,296,089	3,438,953
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	24	24
Allowance for Loan Losses, Collectively Evaluated for Impairment	16,276	14,229
Allowance for Loan Losses, Total	16,300	14,253	11,228
Recorded Investment in Loans, Individually Evaluated for Impairment	1,407	1,412
Recorded Investment in Loans, Collectively Evaluated for Impairment	3,955,263	3,308,136
Recorded Investment in Loans, Total	3,956,670	3,309,548
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	2,015	2,361
Allowance for Loan Losses, Total	2,015	2,361	1,978
Recorded Investment in Loans, Collectively Evaluated for Impairment	1,933,974	2,098,211
Recorded Investment in Loans, Total	1,933,974	2,098,211
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	8,580	3,564
Allowance for Loan Losses, Total	8,580	3,564	1,778
Recorded Investment in Loans, Individually Evaluated for Impairment	144
Recorded Investment in Loans, Collectively Evaluated for Impairment	366,341	428,549
Recorded Investment in Loans, Total	366,485	428,549
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	17,275	4,613
Allowance for Loan Losses, Total	17,275	4,613	1,241
Recorded Investment in Loans, Collectively Evaluated for Impairment	501,681	398,839
Recorded Investment in Loans, Total	501,681	398,839
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	374	442
Allowance for Loan Losses, Total	374	442	310
Recorded Investment in Loans, Individually Evaluated for Impairment		184
Recorded Investment in Loans, Collectively Evaluated for Impairment	75,507	51,021
Recorded Investment in Loans, Total	75,507	51,205
Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	263	397
Allowance for Loan Losses, Total	263	397	$ 931
Recorded Investment in Loans, Collectively Evaluated for Impairment	40,407	27,311
Recorded Investment in Loans, Total	$ 40,407	$ 27,311

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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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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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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