Investment Securities (Amortized Cost, Unrealized Gains And Losses, And Fair Value Of Investment Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	$ 9,380,403	$ 3,738,281
Available-for-sale securities, unrealized gains	100	234
Available-for-sale securities, unrealized losses	(876,517)	(542,349)
Available for sale, at fair value	8,503,986	3,196,166
Investment securities held to maturity	2,344	2,476
Held-to-maturity securities, unrealized gains	714	721
Held-to-maturity securities, unrealized losses	0	0
Held-to-maturity securities, fair value	3,058	3,197
U.S. Treasury and agencies
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	1,557,088	1,035,532
Available-for-sale securities, unrealized gains	2	0
Available-for-sale securities, unrealized losses	(120,538)	(99,358)
Available for sale, at fair value	1,436,552	936,174
Obligations of states and political subdivisions
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	1,074,949	297,610
Available-for-sale securities, unrealized gains	29	231
Available-for-sale securities, unrealized losses	(76,180)	(28,041)
Available for sale, at fair value	998,798	269,800
Mortgage-backed securities and collateralized mortgage obligations
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale securities, amortized cost	6,748,366	2,405,139
Available-for-sale securities, unrealized gains	69	3
Available-for-sale securities, unrealized losses	(679,799)	(414,950)
Available for sale, at fair value	6,068,636	1,990,192
Investment securities held to maturity	2,344	2,476
Held-to-maturity securities, unrealized gains	714	721
Held-to-maturity securities, unrealized losses	0	0
Held-to-maturity securities, fair value	$ 3,058	$ 3,197

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 tax, of unrealized loss 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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Amortized cost of 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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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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