Bank Loans (Risk Category of Loan Portfolio) (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	$ 19,554,758	$ 19,441,467
Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	19,032,267	18,943,697
Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	200,741	211,686
Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	291,895	284,000
Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	29,855	2,084
Residential Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	8,253,851	8,047,647
Residential Real Estate [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	8,248,043	8,042,246
Residential Real Estate [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	3,449	1,456
Residential Real Estate [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	2,359	3,945
Commercial and Industrial [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	3,689,379	3,566,987
Commercial and Industrial [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	3,344,761	3,294,891
Commercial and Industrial [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	166,429	89,302
Commercial and Industrial [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	148,385	180,772
Commercial and Industrial [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	29,804	2,022
Fund Banking [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	3,346,785	3,633,126
Fund Banking [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	3,346,785	3,633,126
Securities-Based Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	2,253,045	2,306,455
Securities-Based Loans [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	2,253,045	2,306,452
Securities-Based Loans [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio		3
Construction And Land [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	1,198,395	1,034,370
Construction And Land [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	1,149,751	963,083
Construction And Land [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio		71,287
Construction And Land [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	48,644
Commercial Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	608,911	660,631
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	485,955	512,171
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	30,827	49,264
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	92,129	99,196
Home Equity Lines Of Credit [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	158,472	136,270
Home Equity Lines Of Credit [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	158,094	135,806
Home Equity Lines Of Credit [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio		377
Home Equity Lines Of Credit [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	378	87
Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	45,920	55,981
Other [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	45,833	55,922
Other [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	36
Other [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Total risk category of loan portfolio	$ 51	$ 59