Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		$ (758,911)	$ (891,412)
Other comprehensive income (loss) before reclassifications to current earnings		168,088	(58,536)
Amounts reclassified to current earnings from accumulated other comprehensive income		(2,308)	5,715
Current period other comprehensive income (loss), before tax		165,780	(52,821)
Income tax (expense) benefit		(41,445)	13,206
Current period other comprehensive income (loss), net of tax		124,335	(39,615)
Ending balance		(634,576)	(931,027)
Unrealized Gains (Losses) on Securities (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[1]	(742,926)	(915,001)
Other comprehensive income (loss) before reclassifications to current earnings	[1]	157,722	(35,671)
Amounts reclassified to current earnings from accumulated other comprehensive income	[1]	(4)	8,469
Current period other comprehensive income (loss), before tax	[1]	157,718	(27,202)
Income tax (expense) benefit	[1]	(39,430)	6,801
Current period other comprehensive income (loss), net of tax	[1]	118,288	(20,401)
Ending balance	[1]	(624,638)	(935,402)
Pension Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(12,059)	(13,596)
Other comprehensive income (loss) before reclassifications to current earnings		0	0
Amounts reclassified to current earnings from accumulated other comprehensive income		229	235
Current period other comprehensive income (loss), before tax		229	235
Income tax (expense) benefit		(57)	(59)
Current period other comprehensive income (loss), net of tax		172	176
Ending balance		(11,887)	(13,420)
Unrealized Gains (Losses) on Cash Flow Hedge Derivatives (2)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[2]	(3,926)	37,185
Other comprehensive income (loss) before reclassifications to current earnings	[2]	10,366	(22,865)
Amounts reclassified to current earnings from accumulated other comprehensive income	[2]	(2,533)	(2,989)
Current period other comprehensive income (loss), before tax	[2]	7,833	(25,854)
Income tax (expense) benefit	[2]	(1,958)	6,464
Current period other comprehensive income (loss), net of tax	[2]	5,875	(19,390)
Ending balance	[2]	$ 1,949	$ 17,795

[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.