Fair Value Measurements (Summary Of Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 84,697,000	$ 71,173,000	$ 73,271,000	$ 67,760,000
Total gains or losses (realized /unrealized), included in earnings	4,217,000	(5,305,000)	12,642,000	(7,602,000)
Total gains or losses (realized /unrealized), included in other comprehensive income	167,000	19,000	(79,000)	729,000
Investment Securities Sold	(518,000)	0	(2,233,000)	0
Investment Securities Called	0	0	0	(600,000)
Discount accretion	7,000	9,000	25,000	42,000
Purchase of private equity securities	10,407,000	2,185,000	15,650,000	9,269,000
Sales And Repayments Of Private Equity Securities	0	(290,000)	(186,000)	(1,840,000)
Capitalized interest/dividends	0	0	35,000	33,000
Purchase Of Risk Participation Agreement	50,000	0	50,000	0
Sale Of Risk Participation Agreement	(31,000)	0	(179,000)	0
Ending balance	98,996,000	67,791,000	98,996,000	67,791,000
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	4,947,000	(4,434,000)	13,223,000	(7,078,000)
State And Municipal Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	15,073,000	16,825,000	17,016,000	16,682,000
Total gains or losses (realized /unrealized), included in earnings	0	0	0	0
Total gains or losses (realized /unrealized), included in other comprehensive income	167,000	19,000	(79,000)	729,000
Investment Securities Sold	(518,000)	0	(2,233,000)	0
Investment Securities Called	0	0	0	(600,000)
Discount accretion	7,000	9,000	25,000	42,000
Purchase of private equity securities	0	0	0	0
Sales And Repayments Of Private Equity Securities	0	0	0	0
Capitalized interest/dividends	0	0	0	0
Purchase Of Risk Participation Agreement	0	0	0	0
Sale Of Risk Participation Agreement	0	0	0	0
Ending balance	14,729,000	16,853,000	14,729,000	16,853,000
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	0	0	0	0
Private Equity Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	68,940,000	53,557,000	55,752,000	50,820,000
Total gains or losses (realized /unrealized), included in earnings	4,275,000	(5,198,000)	12,371,000	(8,028,000)
Total gains or losses (realized /unrealized), included in other comprehensive income	0	0	0	0
Investment Securities Sold	0	0	0	0
Investment Securities Called	0	0	0	0
Discount accretion	0	0	0	0
Purchase of private equity securities	10,407,000	2,185,000	15,650,000	9,269,000
Sales And Repayments Of Private Equity Securities	0	(290,000)	(186,000)	(1,840,000)
Capitalized interest/dividends	0	0	35,000	33,000
Purchase Of Risk Participation Agreement	0	0	0	0
Sale Of Risk Participation Agreement	0	0	0	0
Ending balance	83,622,000	50,254,000	83,622,000	50,254,000
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	4,275,000	(5,198,000)	12,371,000	(7,853,000)
Derivative Level Three Unobservable Inputs [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	684,000	791,000	503,000	258,000
Total gains or losses (realized /unrealized), included in earnings	(58,000)	(107,000)	271,000	426,000
Total gains or losses (realized /unrealized), included in other comprehensive income	0	0	0	0
Investment Securities Sold	0	0	0	0
Investment Securities Called	0	0	0	0
Discount accretion	0	0	0	0
Purchase of private equity securities	0	0	0	0
Sales And Repayments Of Private Equity Securities	0	0	0	0
Capitalized interest/dividends	0	0	0	0
Purchase Of Risk Participation Agreement	50,000	0	50,000	0
Sale Of Risk Participation Agreement	(31,000)	0	(179,000)	0
Ending balance	645,000	684,000	645,000	684,000
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	$ 672,000	$ 764,000	$ 852,000	$ 775,000