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		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance		$ 88,964	$ 101,211	$ 104,344	$ 100,307
Total gains or losses (realized /unrealized), included in earnings		(4,683)	(1,051)	(18,177)	(2,578)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	[1]	1,123	(5)	(372)	359
Investment Securities Called		0	(2,920)	0	(2,920)
Discount accretion		5	37	9	44
Purchase of private equity securities		155	7,829	269	9,889
Sales And Repayments Of Private Equity Securities		0	(6,150)	(69)	(6,150)
Capitalized interest/dividends		29	31	29	31
Purchase Of Risk Participation Agreement		0	26	0	26
Sale Of Risk Participation Agreement		(369)	(73)	(809)	(73)
Ending balance		85,224	98,935	85,224	98,935
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end		(4,682)	(214)	(17,746)	(3,478)
Gains (Losses) included in OCI Attributable to Change in Unrealized Gains (Losses) Relating to Assets Still Held, Total		1,123		(372)
State and Municipal Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance		8,362	14,529	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]	1,123	(5)	(372)	359
Investment Securities Called		0	(2,920)	0	(2,920)
Discount accretion		5	37	9	44
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		9,490	11,641	9,490	11,641
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		1,123		(372)
Private Equity Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance		81,159	85,877	94,122	85,659
Total gains or losses (realized /unrealized), included in earnings		(7,497)	(1,176)	(20,505)	(3,018)
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		155	7,829	269	9,889
Sales And Repayments Of Private Equity Securities		0	(6,150)	(69)	(6,150)
Capitalized interest/dividends		29	31	29	31
Purchase Of Risk Participation Agreement		0	0	0	0
Sale Of Risk Participation Agreement		0	0	0	0
Ending balance		73,846	86,411	73,846	86,411
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end		(7,497)	(1,176)	(20,505)	(4,468)
Gains (Losses) included in OCI Attributable to Change in Unrealized Gains (Losses) Relating to Assets Still Held, Total		0		0
Derivative Level Three Unobservable Inputs [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance		(557)	805	369	490
Total gains or losses (realized /unrealized), included in earnings		2,814	125	2,328	440
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	0
Purchase Of Risk Participation Agreement		0	26	0	26
Sale Of Risk Participation Agreement		(369)	(73)	(809)	(73)
Ending balance		1,888	883	1,888	883
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end		2,815	$ 962	2,759	$ 990
Gains (Losses) included in OCI Attributable to Change in Unrealized Gains (Losses) Relating to Assets Still Held, Total		$ 0		$ 0

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