Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2026	Mar. 31, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		$ (507,690)	$ (758,911)
Other comprehensive income (loss) before reclassifications to current earnings		(42,399)	168,088
Amounts reclassified to current earnings from accumulated other comprehensive income		(136)	(2,308)
Current period other comprehensive income (loss), before tax		(42,535)	165,780
Income tax (expense) benefit		10,633	(41,445)
Current period other comprehensive income (loss), net of tax		(31,902)	124,335
Ending balance		(539,592)	(634,576)
Unrealized Gains (Losses) on Securities (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[1]	(485,071)	(742,926)
Other comprehensive income (loss) before reclassifications to current earnings	[1]	(40,733)	157,722
Amounts reclassified to current earnings from accumulated other comprehensive income	[1]	0	(4)
Current period other comprehensive income (loss), before tax	[1]	(40,733)	157,718
Income tax (expense) benefit	[1]	10,183	(39,430)
Current period other comprehensive income (loss), net of tax	[1]	(30,550)	118,288
Ending balance	[1]	(515,621)	(624,638)
Pension Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(9,623)	(12,059)
Other comprehensive income (loss) before reclassifications to current earnings		0	0
Amounts reclassified to current earnings from accumulated other comprehensive income		138	229
Current period other comprehensive income (loss), before tax		138	229
Income tax (expense) benefit		(35)	(57)
Current period other comprehensive income (loss), net of tax		103	172
Ending balance		(9,520)	(11,887)
Unrealized Gains (Losses) on Cash Flow Hedge Derivatives (2)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[2]	(12,996)	(3,926)
Other comprehensive income (loss) before reclassifications to current earnings	[2]	(1,666)	10,366
Amounts reclassified to current earnings from accumulated other comprehensive income	[2]	(274)	(2,533)
Current period other comprehensive income (loss), before tax	[2]	(1,940)	7,833
Income tax (expense) benefit	[2]	485	(1,958)
Current period other comprehensive income (loss), net of tax	[2]	(1,455)	5,875
Ending balance	[2]	$ (14,451)	$ 1,949

[1] The pre-tax amounts reclassified from accumulated other comprehensive income to current earnings are included in "investment securities gains (losses), net" in the consolidated statements of income.

[2] The pre-tax amounts reclassified from accumulated other comprehensive income to current earnings are included in "interest and fees on loans" in the consolidated statements of income.