Bank Loans (Activity in the Allowance for Loan Losses by Portfolio Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 135,114	$ 122,681	$ 128,292	$ 111,653
Provision	9,208	13,418	20,598	24,911
Charge-offs	(6,972)	(302)	(12,473)	(920)
Recoveries			933	153
Ending Balance	137,350	135,797	137,350	135,797
Commercial and Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	76,354	66,377	67,077	54,143
Provision	10,321	8,584	22,476	21,283
Charge-offs	(6,813)	(302)	(10,624)	(920)
Recoveries			933	153
Ending Balance	79,862	74,659	79,862	74,659
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	15,312	13,429	21,386	12,897
Provision	(2,997)	6,437	(7,381)	6,969
Charge-offs			(1,690)
Ending Balance	12,315	19,866	12,315	19,866
Residential Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	11,242	14,413	13,855	20,441
Provision	28	194	(2,585)	(5,834)
Ending Balance	11,270	14,607	11,270	14,607
Fund Banking [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	12,179	12,178	10,173	11,711
Provision	(1,642)	(660)	364	(193)
Ending Balance	10,537	11,518	10,537	11,518
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	16,379	12,645	11,817	8,568
Provision	3,396	(1,145)	7,958	2,932
Ending Balance	19,775	11,500	19,775	11,500
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	2,813	3,086	3,035	3,157
Provision	40	(68)	(182)	(139)
Ending Balance	2,853	3,018	2,853	3,018
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	362	168	371	364
Provision	(143)	27	(152)	(169)
Ending Balance	219	195	219	195
Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	473	385	578	372
Provision	205	49	100	62
Charge-offs	(159)		(159)
Ending Balance	$ 519	$ 434	$ 519	$ 434