Bank Loans (Risk Category Of Loan Portfolio) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	$ 19,158,620	$ 16,743,487
Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	18,989,865	16,553,018
Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	30,000	54,817
Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	109,670	127,831
Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	29,085	7,821
Residential Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	6,607,825	5,482,026
Residential Real Estate [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	6,606,035	5,480,693
Residential Real Estate [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	74	84
Residential Real Estate [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	1,716	1,249
Commercial and Industrial [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	8,347,410	7,345,753
Commercial and Industrial [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	8,200,462	7,193,435
Commercial and Industrial [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	30,000	38,000
Commercial and Industrial [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	89,596	107,747
Commercial and Industrial [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	27,352	6,571
Securities-Based Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	2,993,552	2,880,158
Securities-Based Loans [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	2,993,549	2,880,158
Securities-Based Loans [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	3
Commercial Real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	629,459	409,847
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	609,459	407,298
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans		2,548
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	20,000
Commercial Real Estate [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans		1
Home Equity Lines Of Credit [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	103,096	82,508
Home Equity Lines Of Credit [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	103,096	82,479
Home Equity Lines Of Credit [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans		29
Construction And Land [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	432,039	511,084
Construction And Land [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	432,039	476,844
Construction And Land [Member] | Special Mention [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans		14,240
Construction And Land [Member] | Substandard [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans		20,000
Other [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	45,239	32,111
Other [Member] | Pass [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	45,225	$ 32,111
Other [Member] | Doubtful [Member]
Financing Receivable Recorded Investment [Line Items]
Gross bank loans	$ 14