Bank Loans (Unpaid Principal Balances Of Loans and Amount Of Allowance Allocated Based Upon Impairment Method by Portfolio Segment) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	$ 8,703	$ 9,105
Allowance for Loan Losses, Collectively Evaluated for Impairment	77,130	58,361
Allowance for Loan Losses, Total	85,833	67,466	$ 45,163
Recorded Investment in Loans, Individually Evaluated for Impairment	24,401	29,213
Recorded Investment in Loans, Collectively Evaluated for Impairment	8,557,246	6,985,208
Recorded Investment in Loans, Total	8,581,647	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	11,204	8,406
Allowance for Loan Losses, Total	11,228	8,430	2,660
Recorded Investment in Loans, Individually Evaluated for Impairment	519	171
Recorded Investment in Loans, Collectively Evaluated for Impairment	2,874,495	2,593,405
Recorded Investment in Loans, Total	2,875,014	2,593,576
Commercial And Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	8,678	9,059
Allowance for Loan Losses, Collectively Evaluated for Impairment	59,689	45,415
Allowance for Loan Losses, Total	68,367	54,474	35,127
Recorded Investment in Loans, Individually Evaluated for Impairment	23,677	28,856
Recorded Investment in Loans, Collectively Evaluated for Impairment	3,280,557	2,409,082
Recorded Investment in Loans, Total	3,304,234	2,437,938
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,978	2,088
Allowance for Loan Losses, Total	1,978	2,088	3,094
Recorded Investment in Loans, Collectively Evaluated for Impairment	1,786,966	1,819,206
Recorded Investment in Loans, Total	1,786,966	1,819,206
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,778	1,520
Allowance for Loan Losses, Total	1,778	1,520	1,363
Recorded Investment in Loans, Collectively Evaluated for Impairment	318,961	116,258
Recorded Investment in Loans, Total	318,961	116,258
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment		20
Allowance for Loan Losses, Collectively Evaluated for Impairment	310	142
Allowance for Loan Losses, Total	310	162	371
Recorded Investment in Loans, Individually Evaluated for Impairment	184	184
Recorded Investment in Loans, Collectively Evaluated for Impairment	37,914	14,855
Recorded Investment in Loans, Total	38,098	15,039
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,241	100
Allowance for Loan Losses, Total	1,241	100	232
Recorded Investment in Loans, Collectively Evaluated for Impairment	138,245	7,896
Recorded Investment in Loans, Total	138,245	7,896
Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	1	2
Allowance for Loan Losses, Collectively Evaluated for Impairment	87	14
Allowance for Loan Losses, Total	88	16	129
Recorded Investment in Loans, Individually Evaluated for Impairment	21	2
Recorded Investment in Loans, Collectively Evaluated for Impairment	120,108	24,506
Recorded Investment in Loans, Total	120,129	24,508
Qualitative [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Collectively Evaluated for Impairment	843	676
Allowance for Loan Losses, Total	$ 843	$ 676	$ 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 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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