INVESTMENTS (Tables)

3 Months Ended

Mar. 31, 2026

Investments, Debt and Equity Securities [Abstract]

Summary of Held-To-Maturity and Available-For-Sale Investment Securities

The following is a summary of HTM and AFS investment securities as of March 31, 2026:


	Held-to-maturity								Available-for-sale
(Dollars in thousands)	Amortized cost		Unrecognized gain		Unrecognized loss		Fair value		Amortized cost		Unrealized gain		Unrealized loss		Fair value
U.S. Treasuries	$	0	$	0	$	0	$	0	$	10,143	$	0	$	(15)	$	10,128
Securities of U.S. government agencies and corporations	0		0		0		0		82,303		121		(249)		82,175
Mortgage-backed securities - residential	0		0		0		0		2,008,226		3,318		(82,957)		1,928,587
Mortgage-backed securities - commercial	26,927		0		(3,468)		23,459		441,285		598		(16,239)		425,644
Collateralized mortgage obligations	5,846		0		(513)		5,333		1,096,428		1,762		(41,555)		1,056,635
Obligations of state and other political subdivisions	8,358		50		(204)		8,204		728,838		743		(94,675)		634,906
Asset-backed securities	0		0		0		0		669,079		1,148		(15,486)		654,741
Other securities	8,500		0		(123)		8,377		162,336		776		(2,905)		160,207
Total	$	49,631	$	50	$	(4,308)	$	45,373	$	5,198,638	$	8,466	$	(254,081)	$	4,953,023

The following is a summary of HTM and AFS investment securities as of December 31, 2025:


	Held-to-maturity								Available-for-sale
(Dollars in thousands)	Amortized cost		Unrecognized gain		Unrecognized loss		Fair value		Amortized cost		Unrealized gain		Unrealized loss		Fair value
U.S. Treasuries	$	0	$	0	$	0	$	0	$	99	$	0	$	(4)	$	95
Securities of U.S. government agencies and corporations	0		0		0		0		0		0		0		0
Mortgage-backed securities - residential	0		0		0		0		1,607,916		11,265		(69,767)		1,549,414
Mortgage-backed securities - commercial	27,373		0		(3,392)		23,981		394,129		1,212		(13,741)		381,600
Collateralized mortgage obligations	6,088		0		(499)		5,589		741,819		3,765		(36,347)		709,237
Obligations of state and other political subdivisions	8,334		60		(179)		8,215		706,668		931		(89,509)		618,090
Asset-backed securities	0		0		0		0		568,366		1,817		(13,639)		556,544
Other securities	16,750		0		(201)		16,549		163,078		1,063		(7,189)		156,952
Total	$	58,545	$	60	$	(4,271)	$	54,334	$	4,182,075	$	20,053	$	(230,196)	$	3,971,932

Summary of Investment Securities by Estimated Maturity

The following table provides a summary of investment securities by contractual maturity as of March 31, 2026, except for residential and commercial mortgage-backed securities, collateralized mortgage obligations and asset-backed securities, which are shown as single totals due to the unpredictability of the timing in principal repayments.


	Held-to-maturity				Available-for-sale
(Dollars in thousands)	Amortized cost		Fair value		Amortized cost		Fair value
By Contractual Maturity:
Due in one year or less	$	1,213	$	1,212	$	34,196	$	34,132
Due after one year through five years	14,290		14,202		95,609		87,628
Due after five years through ten years	0		0		235,436		210,923
Due after ten years	1,355		1,167		618,379		554,733
Mortgage-backed securities - residential	0		0		2,008,226		1,928,587
Mortgage-backed securities - commercial	26,927		23,459		441,285		425,644
Collateralized mortgage obligations	5,846		5,333		1,096,428		1,056,635
Asset-backed securities	0		0		669,079		654,741
Total	$	49,631	$	45,373	$	5,198,638	$	4,953,023

Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value

The following tables provide the fair value and gross unrealized losses of AFS investment securities in an unrealized loss position for which an ACL has not been recorded, aggregated by investment category and the length of time the individual securities have been in a continuous loss position:


	March 31, 2026
	Less than 12 months				12 months or more				Total
(Dollars in thousands)	Fair value		Unrealized loss		Fair value		Unrealized loss		Fair value		Unrealized loss
U.S. Treasuries	$	10,033	$	(10)	$	95	$	(5)	$	10,128	$	(15)
Securities of U.S. Government agencies and corporations	35,470		(249)		0		0		35,470		(249)
Mortgage-backed securities - residential	1,181,376		(15,690)		414,361		(67,267)		1,595,737		(82,957)
Mortgage-backed securities - commercial	189,148		(2,506)		151,568		(13,733)		340,716		(16,239)
Collateralized mortgage obligations	600,352		(5,748)		263,609		(35,807)		863,961		(41,555)
Obligations of state and other political subdivisions	114,099		(2,566)		453,419		(92,109)		567,518		(94,675)
Asset-backed securities	230,177		(1,068)		47,549		(14,418)		277,726		(15,486)
Other securities	27,940		(171)		69,559		(2,734)		97,499		(2,905)
Total	$	2,388,595	$	(28,008)	$	1,400,160	$	(226,073)	$	3,788,755	$	(254,081)


	December 31, 2025
	Less than 12 months				12 months or more				Total
(Dollars in thousands)	Fair value		Unrealized loss		Fair value		Unrealized loss		Fair value		Unrealized loss
U.S. Treasuries	$	0	$	0	$	95	$	(4)	$	95	$	(4)
Securities of U.S. Government agencies and corporations	0		0		0		0		0		0
Mortgage-backed securities - residential	277,394		(1,349)		536,694		(68,418)		814,088		(69,767)
Mortgage-backed securities - commercial	39,084		(108)		166,649		(13,633)		205,733		(13,741)
Collateralized mortgage obligations	56,942		(130)		286,606		(36,217)		343,548		(36,347)
Obligations of state and other political subdivisions	71,825		(511)		466,766		(88,998)		538,591		(89,509)
Asset-backed securities	70,967		(48)		54,351		(13,591)		125,318		(13,639)
Other securities	7,321		(54)		76,141		(7,135)		83,462		(7,189)
Total	$	523,533	$	(2,200)	$	1,587,302	$	(227,996)	$	2,110,835	$	(230,196)

The following tables provide the fair value and gross unrecognized losses of HTM investment securities in an unrecognized loss position for which an ACL has not been recorded, aggregated by investment category and the length of time the individual securities have been in a continuous loss position:


	March 31, 2026
	Less than 12 months				12 months or more				Total
(Dollars in thousands)	Fair value		Unrecognized loss		Fair value		Unrecognized loss		Fair value		Unrecognized loss
U.S. Treasuries	$	0	$	0	$	0	$	0	$	0	$	0
Securities of U.S. Government agencies and corporations	0		0		0		0		0		0
Mortgage-backed securities - residential	0		0		0		0		0		0
Mortgage-backed securities - commercial	0		0		23,459		(3,468)		23,459		(3,468)
Collateralized mortgage obligations	0		0		5,333		(513)		5,333		(513)
Obligations of state and other political subdivisions	3,402		(17)		1,167		(187)		4,569		(204)
Asset-backed securities	0		0		0		0		0		0
Other securities	0		0		8,377		(123)		8,377		(123)
Total	$	3,402	$	(17)	$	38,336	$	(4,291)	$	41,738	$	(4,308)


	December 31, 2025
	Less than 12 months				12 months or more				Total
(Dollars in thousands)	Fair value		Unrecognized loss		Fair value		Unrecognized loss		Fair value		Unrecognized loss
U.S. Treasuries	$	0	$	0	$	0	$	0	$	0	$	0
Securities of U.S. Government agencies and corporations	0		0		0		0		0		0
Mortgage-backed securities - residential	0		0		0		0		0		0
Mortgage-backed securities - commercial	0		0		23,981		(3,392)		23,981		(3,392)
Collateralized mortgage obligations	0		0		5,589		(499)		5,589		(499)
Obligations of state and other political subdivisions	2,273		(4)		1,217		(175)		3,490		(179)
Asset-backed securities	0		0		0		0		0		0
Other securities	0		0		16,549		(201)		16,549		(201)
Total	$	2,273	$	(4)	$	47,336	$	(4,267)	$	49,609	$	(4,271)