Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				$ (1,086,864)	$ 77,080
Other comprehensive income (loss) before reclassifications to current earnings				66,812	(1,123,536)
Amounts reclassified to current earnings from accumulated other comprehensive income				614	(1,762)
Current period other comprehensive income (loss), before tax				67,426	(1,125,298)
Income tax (expense) benefit				(16,857)	281,324
Current period other comprehensive income (loss), net of tax		$ (95,797)	$ (332,494)	50,569	(843,974)
Ending balance		(1,036,295)	(766,894)	(1,036,295)	(766,894)
Unrealized Gains (Losses) on Securities (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[1]			(1,124,915)	23,174
Other comprehensive income (loss) before reclassifications to current earnings	[1]			72,335	(1,123,536)
Amounts reclassified to current earnings from accumulated other comprehensive income	[1]			8,444	9,582
Current period other comprehensive income (loss), before tax	[1]			80,779	(1,113,954)
Income tax (expense) benefit	[1]			(20,195)	278,488
Current period other comprehensive income (loss), net of tax	[1]			60,584	(835,466)
Ending balance	[1]	(1,064,331)	(812,292)	(1,064,331)	(812,292)
Pension Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance				(17,186)	(20,668)
Other comprehensive income (loss) before reclassifications to current earnings				0	0
Amounts reclassified to current earnings from accumulated other comprehensive income				719	860
Current period other comprehensive income (loss), before tax				719	860
Income tax (expense) benefit				(180)	(215)
Current period other comprehensive income (loss), net of tax				539	645
Ending balance		(16,647)	(20,023)	(16,647)	(20,023)
Unrealized Gains (Losses) on Cash Flow Hedge Derivatives (2)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[2]			55,237	74,574
Other comprehensive income (loss) before reclassifications to current earnings	[2]			(5,523)	0
Amounts reclassified to current earnings from accumulated other comprehensive income	[2]			(8,549)	(12,204)
Current period other comprehensive income (loss), before tax	[2]			(14,072)	(12,204)
Income tax (expense) benefit	[2]			3,518	3,051
Current period other comprehensive income (loss), net of tax	[2]			(10,554)	(9,153)
Ending balance	[2]	$ 44,683	$ 65,421	$ 44,683	$ 65,421

[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.