Bank Loans (Activity In The Allowance For Loan Losses By Portfolio Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 35,866	$ 23,923	$ 29,787	$ 20,731
Provision	3,561	3,735	9,643	6,996
Charge-offs	(283)	(27)	(296)	(142)
Recoveries	1	76	11	122
Ending Balance	39,145	27,707	39,145	27,707
Commercial And Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	29,816	19,297	24,748	16,609
Provision	2,631	3,117	7,699	5,805
Charge-offs	(267)		(267)
Ending Balance	32,180	22,414	32,180	22,414
Securities Based Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,731	1,445	1,607	1,099
Provision	172	61	296	407
Ending Balance	1,903	1,506	1,903	1,506
Consumer [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	107	123	105	156
Provision	203	(22)	205	(55)
Charge-offs	(16)		(16)
Recoveries	1	6	1	6
Ending Balance	295	107	295	107
Residential Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,529	904	1,241	787
Provision	346	197	644	425
Charge-offs		(27)	(13)	(142)
Recoveries		48	3	52
Ending Balance	1,875	1,122	1,875	1,122
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	512	286	264	232
Provision	(8)	(36)	233	(24)
Recoveries		14	7	56
Ending Balance	504	264	504	264
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	283	265	290	267
Provision	2	(20)	(5)	(22)
Recoveries		8		8
Ending Balance	285	253	285	253
Construction And Land [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	144		78
Provision	59	47	125	47
Ending Balance	203	47	203	47
Qualitative [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,744	1,603	1,454	1,581
Provision	156	391	446	413
Ending Balance	$ 1,900	$ 1,994	$ 1,900	$ 1,994