Fair Value Measurements (Summary Of Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 71,173	$ 80,994	$ 67,760	$ 80,296
Total gains or losses (realized /unrealized), included in earnings	(5,305)	(2,785)	(7,602)	(6,040)
Total gains or losses (realized /unrealized), included in other comprehensive income	19	317	729	819
Investment securities called	0	(1,100)	(600)	(1,200)
Discount accretion	9	12	42	94
Purchase of private equity securities	2,185	2,894	9,269	8,735
Sales And Repayments Of Private Equity Securities	(290)	(3,315)	(1,840)	(5,713)
Capitalized interest/dividends	0	15	33	77
Sale Of Risk Participation Agreement	0	(33)	0	(69)
Ending balance	67,791	76,999	67,791	76,999
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	(4,434)	(1,995)	(7,078)	(5,677)
State And Municipal Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	16,825	17,679	16,682	17,195
Total gains or losses (realized /unrealized), included in earnings	0	0	0	0
Total gains or losses (realized /unrealized), included in other comprehensive income	19	317	729	819
Investment securities called	0	(1,100)	(600)	(1,200)
Discount accretion	9	12	42	94
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
Sale Of Risk Participation Agreement	0	0	0	0
Ending balance	16,853	16,908	16,853	16,908
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	53,557	62,813	50,820	63,032
Total gains or losses (realized /unrealized), included in earnings	(5,198)	(2,921)	(8,028)	(6,645)
Total gains or losses (realized /unrealized), included in other comprehensive income	0	0	0	0
Investment securities called	0	0	0	0
Discount accretion	0	0	0	0
Purchase of private equity securities	2,185	2,894	9,269	8,735
Sales And Repayments Of Private Equity Securities	(290)	(3,315)	(1,840)	(5,713)
Capitalized interest/dividends	0	15	33	77
Sale Of Risk Participation Agreement	0	0	0	0
Ending balance	50,254	59,486	50,254	59,486
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	(5,198)	(2,921)	(7,853)	(6,545)
Derivative Level Three Unobservable Inputs [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	791	502	258	69
Total gains or losses (realized /unrealized), included in earnings	(107)	136	426	605
Total gains or losses (realized /unrealized), included in other comprehensive income	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
Sale Of Risk Participation Agreement	0	(33)	0	(69)
Ending balance	684	605	684	605
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	$ 764	$ 926	$ 775	$ 868