Bank Loans (Aging Of The Recorded Investment In Past Due Loans) (Details) - USD ($)		Sep. 30, 2015		Dec. 31, 2014		Sep. 30, 2014
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		$ 2,147,000		$ 11,479,000
Current Balance		2,440,196,000		2,105,155,000
Recorded Investment in Loans, Total		2,442,343,000		2,116,634,000		$ 1,921,351,000
Non-accrual		367,000	[1]	4,885,000	[2]
Restructured		328,000	[1]	504,000	[2]
Total		695,000	[1]	5,389,000	[2]
Loans past due 90 days and still accruing interest		0		0
30 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		2,112,000		6,631,000
90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		35,000		4,848,000
Commercial And Industrial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Balance		1,121,643,000		896,853,000
Recorded Investment in Loans, Total		1,121,643,000		896,853,000		833,988,000
Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		21,000		42,000
Current Balance		1,026,176,000		758,246,000
Recorded Investment in Loans, Total		1,026,197,000	[3]	758,288,000	[3]	638,810,000
Non-accrual		21,000	[1]	13,000	[2]
Total		21,000	[1]	13,000	[2]
Consumer [Member] | 30 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		9,000		28,000
Consumer [Member] | 90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		12,000		14,000
Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		2,126,000		11,437,000
Current Balance		258,832,000		421,209,000
Recorded Investment in Loans, Total		260,958,000		432,646,000		418,806,000
Non-accrual		23,000	[1]	4,321,000	[2]
Restructured		328,000	[1]	504,000	[2]
Total		351,000	[1]	4,825,000	[2]
Residential Real Estate [Member] | 30 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		2,103,000		6,603,000
Residential Real Estate [Member] | 90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		23,000		4,834,000
Commercial Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Balance		19,811,000		15,902,000
Recorded Investment in Loans, Total		19,811,000		15,902,000		15,971,000
Non-accrual	[2]			228,000
Total	[2]			228,000
Home Equity Lines Of Credit [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Balance		11,260,000		12,945,000
Recorded Investment in Loans, Total		11,260,000		12,945,000		$ 13,776,000
Non-accrual		323,000	[1]	323,000	[2]
Total		323,000	[1]	$ 323,000	[2]
Construction And Land [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Balance		2,474,000
Recorded Investment in Loans, Total		$ 2,474,000

[1] There were no loans past due 90 days and still accruing interest at September 30, 2015.

[2] There were no loans past due 90 days and still accruing interest at December 31, 2014.

[3] Includes securities-based loans of $ 1.0 billion and $732.8 million at September 30, 2015 and December 31, 2014, respectively.