Investment Securities (Amortized Cost, Unrealized Gains And Losses, And Fair Value Of Investment Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Investment Holdings [Line Items]
Available-for-sale securities, amortized cost	$ 3,800,074	$ 3,864,355
Available-for-sale securities, unrealized gains	938	58,106
Available-for-sale securities, unrealized losses	(384,305)	(52,026)
Available for sale, at fair value	3,416,707	3,870,435
Investment securities held to maturity	2,637	2,744
Held-to-maturity securities, unrealized gains	748	770
Held-to-maturity securities, unrealized losses	0	0
Held-to-maturity securities, fair value	3,385	3,514
U.S. Treasury and agencies
Investment Holdings [Line Items]
Available-for-sale securities, amortized cost	936,537	894,969
Available-for-sale securities, unrealized gains	0	27,279
Available-for-sale securities, unrealized losses	(63,662)	(4,195)
Available for sale, at fair value	872,875	918,053
Obligations of states and political subdivisions
Investment Holdings [Line Items]
Available-for-sale securities, amortized cost	314,260	320,338
Available-for-sale securities, unrealized gains	672	11,734
Available-for-sale securities, unrealized losses	(22,824)	(1,288)
Available for sale, at fair value	292,108	330,784
Mortgage-backed securities and collateralized mortgage obligations
Investment Holdings [Line Items]
Available-for-sale securities, amortized cost	2,549,277	2,649,048
Available-for-sale securities, unrealized gains	266	19,093
Available-for-sale securities, unrealized losses	(297,819)	(46,543)
Available for sale, at fair value	2,251,724	2,621,598
Investment securities held to maturity	2,637	2,744
Held-to-maturity securities, unrealized gains	748	770
Held-to-maturity securities, unrealized losses	0	0
Held-to-maturity securities, fair value	$ 3,385	$ 3,514

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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