Bank Loans (Risk Category Of Loan Portfolio) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	$ 20,899,444	$ 20,602,558
Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	20,666,331	20,427,527
Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	145,274	108,027
Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	77,664	56,899
Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	10,175	10,105
Residential Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	7,494,788	7,371,671
Residential Real Estate [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	7,494,068	7,370,717
Residential Real Estate [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	104	266
Residential Real Estate [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Residential Real Estate [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	616	688
Commercial And Industrial [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	4,755,664	4,897,176
Commercial And Industrial [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	4,583,114	4,743,290
Commercial And Industrial [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	85,336	87,761
Commercial And Industrial [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	77,664	56,899
Commercial And Industrial [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	9,550	9,226
Fund Banking [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	4,623,423	4,182,641
Fund Banking [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	4,623,423	4,182,641
Securities-Based Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	2,558,343	2,724,551
Securities-Based Loans [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	2,558,340	2,724,548
Securities-Based Loans [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Securities-Based Loans [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Securities-Based Loans [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	3	3
Commercial Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	663,325	675,599
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	603,816	655,599
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	59,509	20,000
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Commercial Real Estate [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Construction And Land [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	644,800	593,191
Construction And Land [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	644,800	593,191
Construction And Land [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Construction And Land [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Construction And Land [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0	182
Home Equity Lines Of Credit [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	109,197	107,136
Home Equity Lines Of Credit [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	108,886	106,954
Home Equity Lines Of Credit [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	311
Home Equity Lines Of Credit [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Home Equity Lines Of Credit [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Other [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	49,904	50,593
Other [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	49,884	50,587
Other [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	14
Other [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	0
Other [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	$ 6	$ 6