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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance		$ 85,224	$ 98,935	$ 104,344	$ 100,307
Total gains or losses (realized /unrealized), included in earnings		2,893	1,945	(15,284)	(633)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	[1]	271	(65)	(101)	294
Investment Securities Called		2,000	(1,715)	2,000	(4,635)
Discount accretion		105	36	114	80
Purchase of private equity securities		2,522	5,010	2,791	14,899
Sales And Repayments Of Private Equity Securities		(295)	0	(364)	(6,150)
Capitalized interest/dividends			0	29	31
Purchase Of Risk Participation Agreement		0	200	0	226
Sale Of Risk Participation Agreement			(241)	(809)	(314)
Ending balance		88,720	104,105	88,720	104,105
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end		5,459	2,880	(14,834)	(1,532)
Gains (Losses) included in OCI Attributable to Change in Unrealized Gains (Losses) Relating to Assets Still Held, Total		258	0	(52)	0
State and Municipal Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance		9,490	11,641	9,853	14,158
Total gains or losses (realized /unrealized), included in earnings		0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	[1]	271	(65)	(101)	294
Investment Securities Called		2,000	(1,715)	(2,000)	(4,635)
Discount accretion		105	36	114	80
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
Purchase Of Risk Participation Agreement		0	0	0	0
Sale Of Risk Participation Agreement			0	0	0
Ending balance		7,866	9,897	7,866	9,897
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
Gains (Losses) included in OCI Attributable to Change in Unrealized Gains (Losses) Relating to Assets Still Held, Total		258	0	(52)	0
Private Equity Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance		73,846	86,411	94,122	85,659
Total gains or losses (realized /unrealized), included in earnings		2,389	2,020	(18,116)	(998)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	[1]	0	0	0	0
Investment Securities Called		0	0	0	0
Discount accretion		0	0	0	0
Purchase of private equity securities		2,522	5,010	2,791	14,899
Sales And Repayments Of Private Equity Securities		(295)	0	(364)	(6,150)
Capitalized interest/dividends			0	29	31
Purchase Of Risk Participation Agreement		0	0	0	0
Sale Of Risk Participation Agreement			0	0	0
Ending balance		78,462	93,441	78,462	93,441
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end		2,409	2,020	(18,096)	(2,448)
Gains (Losses) included in OCI Attributable to Change in Unrealized Gains (Losses) Relating to Assets Still Held, Total		0	0	0	0
Derivative Level Three Unobservable Inputs [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance		1,888	883	369	490
Total gains or losses (realized /unrealized), included in earnings		504	(75)	2,832	365
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	[1]	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
Purchase Of Risk Participation Agreement		0	200	0	226
Sale Of Risk Participation Agreement			(241)	(809)	(314)
Ending balance		2,392	767	2,392	767
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end		3,050	860	3,262	916
Gains (Losses) included in OCI Attributable to Change in Unrealized Gains (Losses) Relating to Assets Still Held, Total		$ 0	$ 0	$ 0	$ 0

[1] * Included in "net unrealized gains (losses) on other securities" in the consolidated statements of comprehensive income.