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Investment Securities (Amortized Cost, Unrealized Gains And Losses, And Fair Value Of Investment Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	$ 8,970,189	$ 9,262,777
Available-for-sale securities, unrealized gains	106,896	55,201
Available-for-sale securities, unrealized losses	(400,278)	(488,108)
Available for sale, at fair value	8,676,807	8,829,870
Investment securities held to maturity	2,159	2,300
Held-to-maturity securities, unrealized gains	636	725
Held-to-maturity securities, unrealized losses	0	0
Held-to-maturity securities, fair value	2,795	3,025
U.S. Treasury and agencies
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	1,539,618	1,551,074
Available-for-sale securities, unrealized gains	10,419	6,192
Available-for-sale securities, unrealized losses	(53,780)	(78,874)
Available for sale, at fair value	1,496,257	1,478,392
Obligations of states and political subdivisions
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	1,060,879	1,073,264
Available-for-sale securities, unrealized gains	19,241	20,451
Available-for-sale securities, unrealized losses	(18,530)	(21,610)
Available for sale, at fair value	1,061,590	1,072,105
Mortgage-backed securities and collateralized mortgage obligations
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	6,369,692	6,638,439
Available-for-sale securities, unrealized gains	77,236	28,558
Available-for-sale securities, unrealized losses	(327,968)	(387,624)
Available for sale, at fair value	6,118,960	6,279,373
Investment securities held to maturity	2,159	2,300
Held-to-maturity securities, unrealized gains	636	725
Held-to-maturity securities, unrealized losses	0	0
Held-to-maturity securities, fair value	$ 2,795	$ 3,025

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- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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