Bank Loans (Risk Category of Loan Portfolio) (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	$ 24,574,685	$ 22,066,763
Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	24,107,204	21,594,679
Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	121,805	145,241
Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	224,778	205,690
Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	120,898	121,153
Residential Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	9,619,618	9,254,939
Residential Real Estate [Member] \| Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	9,614,634	9,247,024
Residential Real Estate [Member] \| Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	991	4,427
Residential Real Estate [Member] \| Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	3,993	3,488
Commercial and Industrial [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	4,529,422	4,135,091
Commercial and Industrial [Member] \| Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	4,255,957	3,851,296
Commercial and Industrial [Member] \| Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	47,914	120,212
Commercial and Industrial [Member] \| Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	150,515	80,848
Commercial and Industrial [Member] \| Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	75,036	82,735
Fund Banking [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	5,767,990	4,096,649
Fund Banking [Member] \| Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	5,767,990	4,096,649
Securities-Based Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	2,977,657	2,672,431
Securities-Based Loans [Member] \| Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	2,977,657	2,672,431
Construction And Land [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	977,377	1,214,450
Construction And Land [Member] \| Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	826,884	1,110,498
Construction And Land [Member] \| Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	59,197	20,100
Construction And Land [Member] \| Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	45,434	45,434
Construction And Land [Member] \| Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	45,862	38,418
Commercial Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	412,809	423,474
Commercial Real Estate [Member] \| Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	375,031	348,069
Commercial Real Estate [Member] \| Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	13,603
Commercial Real Estate [Member] \| Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	24,175	75,405
Home Equity Lines Of Credit [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	247,016	225,196
Home Equity Lines Of Credit [Member] \| Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	246,355	224,182
Home Equity Lines Of Credit [Member] \| Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio		499
Home Equity Lines Of Credit [Member] \| Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	661	515
Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	42,796	44,533
Other [Member] \| Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	42,696	44,530
Other [Member] \| Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	$ 100	$ 3