Bank Loans (Activity In The Allowance For Loan Losses By Portfolio Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 88,172	$ 69,497	$ 85,833	$ 67,466
Provision	2,353	4,277	4,636	6,320
Charge-offs	(54)		(110)	(14)
Recoveries	1	1	113	3
Ending Balance	90,472	73,775	90,472	73,775
Commercial And Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	68,566	56,433	68,367	54,474
Provision	743	3,139	954	5,110
Charge-offs	(46)		(58)	(12)
Ending Balance	69,263	59,572	69,263	59,572
Residential Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	11,585	8,779	11,228	8,430
Provision	457	549	727	898
Recoveries			87
Ending Balance	12,042	9,328	12,042	9,328
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	2,227	1,894	1,978	2,088
Provision	84	34	333	(160)
Ending Balance	2,311	1,928	2,311	1,928
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	2,421	1,320	1,778	1,520
Provision	57	352	700	152
Ending Balance	2,478	1,672	2,478	1,672
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,724	199	1,241	100
Provision	678	104	1,161	203
Ending Balance	2,402	303	2,402	303
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	372	164	310	162
Provision	49	64	110	65
Recoveries		1	1	2
Ending Balance	421	229	421	229
Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	146	15	88	16
Provision	40	(2)	118	(2)
Charge-offs	(8)		(52)	(2)
Recoveries	1		25	1
Ending Balance	179	13	179	13
Qualitative [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,131	693	843	676
Provision	245	37	533	54
Ending Balance	$ 1,376	$ 730	$ 1,376	$ 730