Bank Loans (Aging Of The Recorded Investment In Past Due Loans) (Details) - USD ($)		Mar. 31, 2023		Dec. 31, 2022
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		$ 15,597,000		$ 12,612,000
Total		20,899,444,000		20,602,558,000
Non-Accrual		10,600,000	[1]	10,102,000	[2]
Restructured		149,000	[1]	150,000	[2]
Nonperforming loans with no allowance		0	[1]	0	[2]
Total		10,749,000	[1]	10,252,000	[2]
Loans past due 90 days and still accruing interest		0		0
Non-Accrual		10,600,000	[1]	10,102,000	[2]
30 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		4,997,000		2,510,000
90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		10,600,000		10,102,000
Current Balance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		20,883,847,000		20,589,946,000
Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		5,658,000		3,133,000
Total		7,494,788,000		7,371,671,000
Non-Accrual		720,000	[1]	870,000	[2]
Restructured		149,000	[1]	150,000	[2]
Nonperforming loans with no allowance		0	[1]	0	[2]
Total		869,000	[1]	1,020,000	[2]
Non-Accrual		720,000	[1]	870,000	[2]
Residential Real Estate [Member] | 30 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		4,938,000		2,445,000
Residential Real Estate [Member] | 90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		720,000		688,000
Residential Real Estate [Member] | Current Balance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		7,489,130,000		7,368,538,000
Commercial And Industrial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		9,550,000		9,226,000
Total		4,755,664,000		4,897,176,000
Non-Accrual		9,550,000	[1]	9,226,000	[2]
Total		9,550,000	[1]	9,226,000	[2]
Non-Accrual		9,550,000	[1]	9,226,000	[2]
Commercial And Industrial [Member] | 30 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		0		0
Commercial And Industrial [Member] | 90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		9,550,000		9,226,000
Commercial And Industrial [Member] | Current Balance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		4,746,114,000		4,887,950,000
Fund Banking [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total		4,623,423,000		4,182,641,000
Fund Banking [Member] | Current Balance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		4,623,423,000		4,182,641,000
Securities-Based Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total		2,558,343,000		2,724,551,000
Securities-Based Loans [Member] | Current Balance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		2,558,343,000		2,724,551,000
Commercial Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due				0
Total		663,325,000		675,599,000
Commercial Real Estate [Member] | 90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		0		0
Commercial Real Estate [Member] | Current Balance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		663,325,000		675,599,000
Construction And Land [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due				0
Total		644,800,000		593,191,000
Construction And Land [Member] | 90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due				0
Construction And Land [Member] | Current Balance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		644,800,000		593,191,000
Home Equity Lines Of Credit [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		332,000		211,000
Total		109,197,000		107,136,000
Non-Accrual	[1]	310,000
Total	[1]	310,000
Non-Accrual	[1]	310,000
Home Equity Lines Of Credit [Member] | 30 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		22,000		29,000
Home Equity Lines Of Credit [Member] | 90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		310,000		182,000
Home Equity Lines Of Credit [Member] | Current Balance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		108,865,000		106,925,000
Other [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		57,000		42,000
Total		49,904,000		50,593,000
Non-Accrual		20,000	[1]	6,000	[2]
Nonperforming loans with no allowance		0	[1]	0	[2]
Total		20,000	[1]	6,000	[2]
Non-Accrual		20,000	[1]	6,000	[2]
Other [Member] | 30 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		37,000		36,000
Other [Member] | 90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		20,000		6,000
Other [Member] | Current Balance [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		$ 49,847,000		$ 50,551,000

[1] There were no loans past due 90 days and still accruing interest at March 31, 2023

[2] There were no loans past due 90 days and still accruing interest at December 31, 2022.