Bank Loans (Recorded Balances Of Loans and Amount Of Allowance Allocated Based Upon Impairment Method by Portfolio Segment) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	$ 9,109	$ 9,105
Allowance for Loan Losses, Collectively Evaluated for Impairment	60,388	58,361
Allowance for Loan Losses, Total	69,497	67,466	$ 51,298	$ 45,163
Recorded Investment in Loans, Individually Evaluated for Impairment	23,994	29,213
Recorded Investment in Loans, Collectively Evaluated for Impairment	7,130,667	6,985,208
Recorded Investment in Loans, Total	7,154,661	7,014,421
Residential Real Estate [Member]
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	8,755	8,406
Allowance for Loan Losses, Total	8,779	8,430	4,190	2,660
Recorded Investment in Loans, Individually Evaluated for Impairment	170	171
Recorded Investment in Loans, Collectively Evaluated for Impairment	2,633,899	2,593,405
Recorded Investment in Loans, Total	2,634,069	2,593,576
Commercial And Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	9,063	9,059
Allowance for Loan Losses, Collectively Evaluated for Impairment	47,370	45,415
Allowance for Loan Losses, Total	56,433	54,474	38,789	35,127
Recorded Investment in Loans, Individually Evaluated for Impairment	23,638	28,856
Recorded Investment in Loans, Collectively Evaluated for Impairment	2,530,033	2,409,082
Recorded Investment in Loans, Total	2,553,671	2,437,938
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,894	2,088
Allowance for Loan Losses, Total	1,894	2,088	3,393	3,094
Recorded Investment in Loans, Collectively Evaluated for Impairment	1,809,281	1,819,206
Recorded Investment in Loans, Total	1,809,281	1,819,206
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,320	1,520
Allowance for Loan Losses, Total	1,320	1,520	1,618	1,363
Recorded Investment in Loans, Collectively Evaluated for Impairment	101,591	116,258
Recorded Investment in Loans, Total	101,591	116,258
Consumer [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	2	2
Allowance for Loan Losses, Collectively Evaluated for Impairment	13	14
Allowance for Loan Losses, Total	15	16	107	129
Recorded Investment in Loans, Individually Evaluated for Impairment	2	2
Recorded Investment in Loans, Collectively Evaluated for Impairment	24,697	24,506
Recorded Investment in Loans, Total	24,699	24,508
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	20	20
Allowance for Loan Losses, Collectively Evaluated for Impairment	144	142
Allowance for Loan Losses, Total	164	162	285	371
Recorded Investment in Loans, Individually Evaluated for Impairment	184	184
Recorded Investment in Loans, Collectively Evaluated for Impairment	14,829	14,855
Recorded Investment in Loans, Total	15,013	15,039
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	199	100
Allowance for Loan Losses, Total	199	100	437	232
Recorded Investment in Loans, Collectively Evaluated for Impairment	16,337	7,896
Recorded Investment in Loans, Total	16,337	7,896
Qualitative [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	693	676
Allowance for Loan Losses, Total	$ 693	$ 676	$ 2,479	$ 2,187

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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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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