Bank Loans (Schedule Of Balance And Associated Percentage Of Each Major Loan Category In Bank Loan Portfolio) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross bank loans	$ 10,156,675	$ 9,752,616
Unamortized loan discount, net	(6,148)	(6,588)
Loans in process	(53,953)	(27,717)
Unamortized loan fees, net	728	1,310
Allowance for loan losses	(102,802)	(95,579)	$ (88,172)	$ (85,833)
Loans held for investment, net	$ 9,994,500	$ 9,624,042
Gross bank loans, Percent	100.00%	100.00%
Commercial And Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross bank loans	$ 3,813,862	$ 3,438,953
Allowance for loan losses	$ (59,962)	$ (69,949)	(68,566)	(68,367)
Gross bank loans, Percent	37.60%	35.30%
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross bank loans	$ 3,495,136	$ 3,309,548
Allowance for loan losses	$ (19,985)	$ (14,253)	(11,585)	(11,228)
Gross bank loans, Percent	34.40%	33.90%
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross bank loans	$ 399,732	$ 428,549
Allowance for loan losses	$ (8,165)	$ (3,564)	(2,421)	(1,778)
Gross bank loans, Percent	3.90%	4.40%
Construction And Land [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross bank loans	$ 412,410	$ 398,839
Allowance for loan losses	$ (10,953)	$ (4,613)	(1,724)	(1,241)
Gross bank loans, Percent	4.10%	4.10%
Home Equity Lines Of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross bank loans	$ 57,402	$ 51,205
Allowance for loan losses	$ (539)	$ (442)	(372)	(310)
Gross bank loans, Percent	0.60%	0.50%
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross bank loans	$ 32,762	$ 27,311
Allowance for loan losses	$ (283)	$ (194)	(146)	(88)
Gross bank loans, Percent	0.20%	0.30%
Securities-Based Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross bank loans	$ 1,945,371	$ 2,098,211
Allowance for loan losses	$ (2,915)	$ (2,361)	$ (2,227)	$ (1,978)
Gross bank loans, Percent	19.20%	21.50%

Loans and leases payable receivable loans in process.

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Loans receivable held for investment net not part of disposal group mortgage.

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Percentage of loans and leases receivable gross carrying amount.

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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 of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts 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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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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