Investment Securities - Amortized Cost and Fair Value of Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Available for sale debt securities
Amortized Cost	$ 2,097,906	$ 2,190,448
Unrealized Gains	1,922	406
Unrealized Losses	(208,174)	(264,338)
Total available-for-sale securities	1,891,654	1,926,516
Held to maturity securities
Amortized Cost	3,658,814	3,790,650
Unrealized Gains	217	201
Unrealized Losses	(428,333)	(528,342)
Total held-to-maturity securities	3,230,698	3,262,509
Available-for-sale investment securities
Accrued interest receivable related to available-for-sale investment securities	5,000	5,600
Accrued interest receivable related to held to maturity investment securities	6,300	6,600
Collateralized loan obligations
Available for sale debt securities
Amortized Cost	132,796	173,152
Unrealized Gains	270	323
Total available-for-sale securities	133,066	173,475
Government agency debt securities
Available for sale debt securities
Amortized Cost		8,170
Unrealized Losses		(23)
Total available-for-sale securities		8,147
Held to maturity securities
Amortized Cost	47,692	49,267
Unrealized Losses	(3,837)	(5,398)
Total held-to-maturity securities	43,855	43,869
Residential - Government agency
Available for sale debt securities
Amortized Cost	35,295	37,473
Unrealized Gains	286
Unrealized Losses	(1,209)	(1,614)
Total available-for-sale securities	34,372	35,859
Held to maturity securities
Amortized Cost	39,037	40,888
Unrealized Losses	(5,310)	(6,579)
Total held-to-maturity securities	33,727	34,309
Residential - Government-sponsored enterprises
Available for sale debt securities
Amortized Cost	786,643	840,836
Unrealized Gains	348
Unrealized Losses	(72,653)	(102,723)
Total available-for-sale securities	714,338	738,113
Held to maturity securities
Amortized Cost	89,907	92,573
Unrealized Losses	(12,880)	(14,854)
Total held-to-maturity securities	77,027	77,719
Commercial - Government agency
Available for sale debt securities
Amortized Cost	243,434	249,348
Unrealized Losses	(49,424)	(53,223)
Total available-for-sale securities	194,010	196,125
Held to maturity securities
Amortized Cost	30,779	31,009
Unrealized Losses	(8,140)	(8,666)
Total held-to-maturity securities	22,639	22,343
Commercial - Government-sponsored enterprises
Available for sale debt securities
Amortized Cost	45,844	48,015
Unrealized Losses	(1,931)	(3,107)
Total available-for-sale securities	43,913	44,908
Held to maturity securities
Amortized Cost	1,100,422	1,114,549
Unrealized Gains	217	201
Unrealized Losses	(124,704)	(149,244)
Total held-to-maturity securities	975,935	965,506
Commercial - Non-agency
Available for sale debt securities
Amortized Cost	88,812	22,000
Unrealized Gains	504	83
Total available-for-sale securities	89,316	22,083
Government agency
Available for sale debt securities
Amortized Cost	426,641	452,038
Unrealized Gains	119
Unrealized Losses	(42,773)	(54,914)
Total available-for-sale securities	383,987	397,124
Held to maturity securities
Amortized Cost	863,939	907,565
Unrealized Losses	(100,312)	(126,020)
Total held-to-maturity securities	763,627	781,545
Government-sponsored enterprises
Available for sale debt securities
Amortized Cost	338,441	359,416
Unrealized Gains	395
Unrealized Losses	(40,184)	(48,734)
Total available-for-sale securities	298,652	310,682
Held to maturity securities
Amortized Cost	1,432,249	1,500,212
Unrealized Losses	(168,283)	(210,721)
Total held-to-maturity securities	1,263,966	1,289,491
Debt securities issued by states and political subdivisions
Held to maturity securities
Amortized Cost	54,789	54,587
Unrealized Losses	(4,867)	(6,860)
Total held-to-maturity securities	$ 49,922	$ 47,727

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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