Bank Loans (Activity In The Allowance For Loan Losses By Portfolio Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 67,466	$ 45,163
Provision	18,366	25,320
Charge-offs	(14)	(3,058)
Recoveries	15	41
Ending Balance	85,833	67,466
Commercial And Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	54,474	35,127
Provision	13,896	19,666
Charge-offs	(12)	(355)
Recoveries	9	36
Ending Balance	68,367	54,474
Residential Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	8,430	2,660
Provision	2,798	5,770
Ending Balance	11,228	8,430
Securities-Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	2,088	3,094
Provision	(110)	(1,006)
Ending Balance	1,978	2,088
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,520	1,363
Provision	258	2,860
Charge-offs		(2,703)
Ending Balance	1,778	1,520
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	100	232
Provision	1,141	(132)
Ending Balance	1,241	100
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	162	371
Provision	145	(212)
Recoveries	3	3
Ending Balance	310	162
Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	16	129
Provision	71	(115)
Charge-offs	(2)
Recoveries	3	2
Ending Balance	88	16
Qualitative [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	676	2,187
Provision	167	(1,511)
Ending Balance	$ 843	$ 676