Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				$ (891,412)	$ (1,086,864)
Other comprehensive income (loss) before reclassifications to current earnings				(70,677)	66,812
Amounts reclassified to current earnings from accumulated other comprehensive income				182,137	614
Current period other comprehensive income (loss), before tax				111,460	67,426
Income tax (expense) benefit				(27,865)	(16,857)
Current period other comprehensive income (loss), net of tax		$ 123,210	$ (95,797)	83,595	50,569
Ending balance		(807,817)	(1,036,295)	(807,817)	(1,036,295)
Unrealized Gains (Losses) on Securities (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[1]			(915,001)	(1,124,915)
Other comprehensive income (loss) before reclassifications to current earnings	[1]			(41,310)	72,335
Amounts reclassified to current earnings from accumulated other comprehensive income	[1]			187,543	8,444
Current period other comprehensive income (loss), before tax	[1]			146,233	80,779
Income tax (expense) benefit	[1]			(36,558)	(20,195)
Current period other comprehensive income (loss), net of tax	[1]			109,675	60,584
Ending balance	[1]	(805,326)	(1,064,331)	(805,326)	(1,064,331)
Pension Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				(13,596)	(17,186)
Other comprehensive income (loss) before reclassifications to current earnings				0	0
Amounts reclassified to current earnings from accumulated other comprehensive income				471	719
Current period other comprehensive income (loss), before tax				471	719
Income tax (expense) benefit				(118)	(180)
Current period other comprehensive income (loss), net of tax				353	539
Ending balance		(13,243)	(16,647)	(13,243)	(16,647)
Unrealized Gains (Losses) on Cash Flow Hedge Derivatives (2)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[2]			37,185	55,237
Other comprehensive income (loss) before reclassifications to current earnings	[2]			(29,367)	(5,523)
Amounts reclassified to current earnings from accumulated other comprehensive income	[2]			(5,877)	(8,549)
Current period other comprehensive income (loss), before tax	[2]			(35,244)	(14,072)
Income tax (expense) benefit	[2]			8,811	3,518
Current period other comprehensive income (loss), net of tax	[2]			(26,433)	(10,554)
Ending balance	[2]	$ 10,752	$ 44,683	$ 10,752	$ 44,683

[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.