Investment Securities - Amortized Cost and Fair Value of Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Available for sale debt securities
Amortized Cost	$ 2,275,837	$ 2,246,716
Unrealized Gains	2,715	6,897
Unrealized Losses	(183,853)	(177,380)
Total available-for-sale securities	2,094,699	2,076,233
Held to maturity securities
Amortized Cost	3,411,684	3,533,082
Unrealized Gains		227
Unrealized Losses	(376,209)	(344,534)
Total held-to-maturity securities	3,035,475	3,188,775
Available-for-sale investment securities
Accrued interest receivable related to available-for-sale investment securities	5,000	5,500
Accrued interest receivable related to held to maturity investment securities	5,900	6,100
Collateralized loan obligations
Available for sale debt securities
Amortized Cost	44,348	76,497
Unrealized Gains	28	92
Total available-for-sale securities	44,376	76,589
Government agency debt securities
Held to maturity securities
Amortized Cost	44,479	46,182
Unrealized Losses	(3,629)	(3,235)
Total held-to-maturity securities	40,850	42,947
Residential - Government agency
Available for sale debt securities
Amortized Cost	25,704	30,948
Unrealized Gains	419	498
Unrealized Losses	(1,086)	(1,079)
Total available-for-sale securities	25,037	30,367
Held to maturity securities
Amortized Cost	35,787	37,081
Unrealized Losses	(4,431)	(4,462)
Total held-to-maturity securities	31,356	32,619
Residential - Government-sponsored enterprises
Available for sale debt securities
Amortized Cost	925,419	933,206
Unrealized Gains	1,102	3,115
Unrealized Losses	(61,311)	(58,106)
Total available-for-sale securities	865,210	878,215
Held to maturity securities
Amortized Cost	83,559	86,681
Unrealized Losses	(10,798)	(10,661)
Total held-to-maturity securities	72,761	76,020
Commercial - Government agency
Available for sale debt securities
Amortized Cost	230,216	237,192
Unrealized Losses	(46,674)	(46,015)
Total available-for-sale securities	183,542	191,177
Held to maturity securities
Amortized Cost	30,162	30,796
Unrealized Losses	(7,289)	(7,537)
Total held-to-maturity securities	22,873	23,259
Commercial - Government-sponsored enterprises
Available for sale debt securities
Amortized Cost	39,776	42,798
Unrealized Losses	(754)	(1,199)
Total available-for-sale securities	39,022	41,599
Held to maturity securities
Amortized Cost	1,072,102	1,088,838
Unrealized Gains		227
Unrealized Losses	(102,683)	(95,314)
Total held-to-maturity securities	969,419	993,751
Commercial - Non-agency
Available for sale debt securities
Amortized Cost	258,824	128,464
Unrealized Gains	735	589
Unrealized Losses	(49)	(39)
Total available-for-sale securities	259,510	129,014
Government agency
Available for sale debt securities
Amortized Cost	433,114	461,160
Unrealized Gains	217	1,756
Unrealized Losses	(39,041)	(36,640)
Total available-for-sale securities	394,290	426,276
Held to maturity securities
Amortized Cost	787,083	823,423
Unrealized Losses	(94,631)	(84,609)
Total held-to-maturity securities	692,452	738,814
Government-sponsored enterprises
Available for sale debt securities
Amortized Cost	318,436	336,451
Unrealized Gains	214	847
Unrealized Losses	(34,938)	(34,302)
Total available-for-sale securities	283,712	302,996
Held to maturity securities
Amortized Cost	1,303,309	1,365,087
Unrealized Losses	(147,942)	(135,145)
Total held-to-maturity securities	1,155,367	1,229,942
Debt securities issued by states and political subdivisions
Held to maturity securities
Amortized Cost	55,203	54,994
Unrealized Losses	(4,806)	(3,571)
Total held-to-maturity securities	$ 50,397	$ 51,423

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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