Derivative Financial Instruments (Rollforward Of Amounts In Accumulated Other Comprehensive Income Related To Interest Rate Swaps Designated As Cash Flow Hedges) (Detail) - Interest rate contract - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Rollforward of AOCI from Cash Flow Hedging Derivatives [Roll Forward]
Unrealized gain at beginning of period	$ 44,692	$ 76,389	$ 10,026	$ 36,908
Amount reclassified from accumulated other comprehensive income or loss to interest income or expense on deposits, loans, and other borrowings	14,092	1,012	17,664	6,365
Amount of gain recognized in other comprehensive income or loss	(120,523)	1,363	(89,429)	35,491
Unrealized gain at end of period	$ (61,739)	$ 78,764	$ (61,739)	$ 78,764