Investment Securities (Tables)

3 Months Ended

Mar. 31, 2024

Investment Securities

Schedule of amortized cost and fair value of securities

	March 31, 2024								December 31, 2023
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
U.S. Treasury and government agency debt securities	$	13,254	$	—	$	(433)	$	12,821	$	33,169	$	—	$	(666)	$	32,503
Government-sponsored enterprises debt securities		20,000		—		(371)		19,629		20,000		—		(408)		19,592
Mortgage-backed securities:
Residential - Government agency		10,959		—		(1,350)		9,609		11,303		—		(1,121)		10,182
Residential - Government-sponsored enterprises		868,033		—		(114,648)		753,385		895,421		—		(112,124)		783,297
Commercial - Government agency		264,691		—		(51,297)		213,394		268,944		—		(50,270)		218,674
Commercial - Government-sponsored enterprises		90,441		—		(6,951)		83,490		93,459		—		(7,028)		86,431
Commercial - Non-agency		21,968		142		—		22,110		21,964		—		(281)		21,683
Collateralized mortgage obligations:
Government agency		523,160		—		(70,997)		452,163		538,718		—		(67,568)		471,150
Government-sponsored enterprises		413,731		—		(60,670)		353,061		425,826		—		(61,856)		363,970
Collateralized loan obligations		239,872		383		(579)		239,676		249,871		43		(2,060)		247,854
Total available-for-sale securities	$	2,466,109	$	525	$	(307,296)	$	2,159,338	$	2,558,675	$	43	$	(303,382)	$	2,255,336
Government agency debt securities	$	51,904	$	—	$	(5,300)	$	46,604	$	52,051	$	—	$	(4,497)	$	47,554
Mortgage-backed securities:
Residential - Government agency		42,961		—		(6,209)		36,752		43,885		—		(5,189)		38,696
Residential - Government-sponsored enterprises		97,914		—		(13,466)		84,448		99,379		—		(11,013)		88,366
Commercial - Government agency		30,853		—		(7,651)		23,202		30,795		—		(7,017)		23,778
Commercial - Government-sponsored enterprises		1,127,321		167		(144,378)		983,110		1,129,738		195		(130,757)		999,176
Collateralized mortgage obligations:
Government agency		972,199		—		(125,164)		847,035		989,130		—		(109,471)		879,659
Government-sponsored enterprises		1,610,563		—		(209,655)		1,400,908		1,642,274		—		(193,897)		1,448,377
Debt securities issued by states and political subdivisions		54,296		—		(5,645)		48,651		54,197		—		(4,947)		49,250
Total held-to-maturity securities	$	3,988,011	$	167	$	(517,468)	$	3,470,710	$	4,041,449	$	195	$	(466,788)	$	3,574,856

Schedule of amortized cost and fair value of debt securities by contractual maturity

	March 31, 2024
	Amortized		Fair
(dollars in thousands)	Cost		Value
Available-for-sale securities
Due in one year or less	$	13,254	$	12,821
Due after one year through five years		29,275		28,885
Due after five years through ten years		87,696		87,617
Due after ten years		164,869		164,913
		295,094		294,236
Mortgage-backed securities:
Residential - Government agency		10,959		9,609
Residential - Government-sponsored enterprises		868,033		753,385
Commercial - Government agency		264,691		213,394
Commercial - Government-sponsored enterprises		90,441		83,490
Total mortgage-backed securities		1,234,124		1,059,878
Collateralized mortgage obligations:
Government agency		523,160		452,163
Government-sponsored enterprises		413,731		353,061
Total collateralized mortgage obligations		936,891		805,224
Total available-for-sale securities	$	2,466,109	$	2,159,338
Held-to-maturity securities
Due in one year or less	$	—	$	—
Due after one year through five years		—		—
Due after five years through ten years		22,132		20,121
Due after ten years		84,068		75,134
		106,200		95,255
Mortgage-backed securities:
Residential - Government agency		42,961		36,752
Residential - Government-sponsored enterprises		97,914		84,448
Commercial - Government agency		30,853		23,202
Commercial - Government-sponsored enterprises		1,127,321		983,110
Total mortgage-backed securities		1,299,049		1,127,512
Collateralized mortgage obligations:
Government agency		972,199		847,035
Government-sponsored enterprises		1,610,563		1,400,908
Total collateralized mortgage obligations		2,582,762		2,247,943
Total held-to-maturity securities	$	3,988,011	$	3,470,710

Schedule of gross unrealized losses and fair values of securities in a continuous loss position

	Time in Continuous Loss as of March 31, 2024
	Less Than 12 Months				12 Months or More				Total
	Unrealized				Unrealized				Unrealized
(dollars in thousands)	Losses		Fair Value		Losses		Fair Value		Losses		Fair Value
U.S. Treasury and government agency debt securities	$	—	$	—	$	(433)	$	12,821	$	(433)	$	12,821
Government-sponsored enterprises debt securities		—		—		(371)		19,629		(371)		19,629
Mortgage-backed securities:
Residential - Government agency		—		—		(1,350)		9,609		(1,350)		9,609
Residential - Government-sponsored enterprises		—		—		(114,648)		753,385		(114,648)		753,385
Commercial - Government agency		—		—		(51,297)		213,394		(51,297)		213,394
Commercial - Government-sponsored enterprises		—		—		(6,951)		83,490		(6,951)		83,490
Collateralized mortgage obligations:
Government agency		—		—		(70,997)		452,163		(70,997)		452,163
Government-sponsored enterprises		—		—		(60,670)		353,061		(60,670)		353,061
Collateralized loan obligations		(8)		8,492		(571)		99,029		(579)		107,521
Total available-for-sale securities with unrealized losses	$	(8)	$	8,492	$	(307,288)	$	1,996,581	$	(307,296)	$	2,005,073

	Time in Continuous Loss as of December 31, 2023
	Less Than 12 Months				12 Months or More				Total
	Unrealized				Unrealized				Unrealized
(dollars in thousands)	Losses		Fair Value		Losses		Fair Value		Losses		Fair Value
U.S. Treasury and government agency debt securities	$	—	$	—	$	(666)	$	32,503	$	(666)	$	32,503
Government-sponsored enterprises debt securities		—		—		(408)		19,592		(408)		19,592
Mortgage-backed securities:
Residential - Government agency		—		—		(1,121)		10,182		(1,121)		10,182
Residential - Government-sponsored enterprises		—		—		(112,124)		783,297		(112,124)		783,297
Commercial - Government agency		—		—		(50,270)		218,674		(50,270)		218,674
Commercial - Government-sponsored enterprises		—		—		(7,028)		86,431		(7,028)		86,431
Commercial - Non-agency		—		—		(281)		21,683		(281)		21,683
Collateralized mortgage obligations:
Government agency		—		—		(67,568)		471,150		(67,568)		471,150
Government-sponsored enterprises		—		—		(61,856)		363,970		(61,856)		363,970
Collateralized loan obligations		(564)		63,667		(1,496)		163,126		(2,060)		226,793
Total available-for-sale securities with unrealized losses	$	(564)	$	63,667	$	(302,818)	$	2,170,608	$	(303,382)	$	2,234,275