Bank Loans (Activity in the Allowance for Loan Losses by Portfolio Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 130,213	$ 117,162	$ 128,292	$ 111,653
Provision	6,832	6,117	11,390	11,493
Charge-offs	(1,931)	(598)	(5,501)	(618)
Recoveries			933	153
Ending Balance	135,114	122,681	135,114	122,681
Commercial and Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	65,887	55,734	67,077	54,143
Provision	10,708	11,241	12,155	12,699
Charge-offs	(241)	(598)	(3,811)	(618)
Recoveries			933	153
Ending Balance	76,354	66,377	76,354	66,377
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	18,589	10,317	11,817	8,568
Provision	(2,210)	2,328	4,562	4,077
Ending Balance	16,379	12,645	16,379	12,645
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	20,689	11,566	21,386	12,897
Provision	(3,687)	1,863	(4,384)	532
Charge-offs	(1,690)		(1,690)
Ending Balance	15,312	13,429	15,312	13,429
Fund Banking [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	8,763	12,943	10,173	11,711
Provision	3,416	(765)	2,006	467
Ending Balance	12,179	12,178	12,179	12,178
Residential Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	12,507	22,696	13,855	20,441
Provision	(1,265)	(8,283)	(2,613)	(6,028)
Ending Balance	11,242	14,413	11,242	14,413
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	3,068	3,117	3,035	3,157
Provision	(255)	(31)	(222)	(71)
Ending Balance	2,813	3,086	2,813	3,086
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	246	412	371	364
Provision	116	(244)	(9)	(196)
Ending Balance	362	168	362	168
Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	464	377	578	372
Provision	9	8	(105)	13
Ending Balance	$ 473	$ 385	$ 473	$ 385