Bank Loans (Aging Of The Recorded Investment In Past Due Loans) (Details) - USD ($)	Jun. 30, 2015		Dec. 31, 2014		Jun. 30, 2014
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 11,196,000		$ 11,479,000
Current Balance	2,464,619,000		2,105,155,000
Recorded Investment in Loans, Total	2,475,815,000		2,116,634,000		$ 1,816,666,000
Non-accrual	5,132,000	[1]	4,885,000	[2]
Restructured	748,000	[1]	504,000	[2]
Total	5,880,000	[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	6,038,000		6,631,000
90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	5,158,000		4,848,000
Commercial And Industrial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Balance	1,010,810,000		896,853,000
Recorded Investment in Loans, Total	1,010,810,000		896,853,000		750,071,000
Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	27,000		42,000
Current Balance	983,332,000		758,246,000
Recorded Investment in Loans, Total	983,359,000	[3]	758,288,000	[3]	624,700,000
Non-accrual	19,000	[1]	13,000	[2]
Total	19,000	[1]	13,000	[2]
Consumer [Member] | 30 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	18,000		28,000
Consumer [Member] | 90 or More Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	9,000		14,000
Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	11,169,000		11,437,000
Current Balance	437,825,000		421,209,000
Recorded Investment in Loans, Total	448,994,000		432,646,000		411,439,000
Non-accrual	4,571,000	[1]	4,321,000	[2]
Restructured	748,000	[1]	504,000	[2]
Total	5,319,000	[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	6,020,000		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	5,149,000		4,834,000
Commercial Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Balance	20,053,000		15,902,000
Recorded Investment in Loans, Total	20,053,000		15,902,000		16,055,000
Non-accrual	219,000	[1]	228,000	[2]
Total	219,000	[1]	228,000	[2]
Home Equity Lines Of Credit [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Current Balance	12,599,000		12,945,000
Recorded Investment in Loans, Total	12,599,000		12,945,000		$ 14,401,000
Non-accrual	323,000	[1]	323,000	[2]
Total	$ 323,000	[1]	$ 323,000	[2]

[1] There were no loans past due 90 days and still accruing interest at June 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 $ 963.1 million and $732.8 million at June 30, 2015 and December 31, 2014, respectively.