Investment Securities (Tables)

6 Months Ended

Jun. 30, 2023

Investment Securities

Schedule of amortized cost and fair value of securities

	June 30, 2023								December 31, 2022
	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	$	128,594	$	—	$	(11,709)	$	116,885	$	163,309	$	—	$	(12,327)	$	150,982
Government-sponsored enterprises debt securities		45,000		—		(760)		44,240		45,000		—		(699)		44,301
Mortgage-backed securities:
Residential - Government agency		63,486		—		(6,284)		57,202		66,792		—		(7,069)		59,723
Residential - Government-sponsored enterprises		1,229,375		—		(146,383)		1,082,992		1,317,718		—		(157,263)		1,160,455
Commercial - Government agency		276,365		—		(50,903)		225,462		282,700		—		(44,847)		237,853
Commercial - Government-sponsored enterprises		96,441		—		(8,544)		87,897		130,612		—		(11,039)		119,573
Commercial - Non-agency		21,964		—		(585)		21,379		21,964		—		(493)		21,471
Collateralized mortgage obligations:
Government agency		688,844		—		(83,623)		605,221		738,524		—		(85,202)		653,322
Government-sponsored enterprises		496,867		—		(69,387)		427,480		533,103		—		(70,971)		462,132
Collateralized loan obligations		249,889		—		(9,275)		240,614		249,877		50		(8,606)		241,321
Total available-for-sale securities	$	3,296,825	$	—	$	(387,453)	$	2,909,372	$	3,549,599	$	50	$	(398,516)	$	3,151,133
Government agency debt securities	$	53,189	$	—	$	(5,675)	$	47,514	$	54,318	$	—	$	(5,674)	$	48,644
Mortgage-backed securities:
Residential - Government agency		45,097		—		(5,484)		39,613		46,302		—		(6,294)		40,008
Residential - Government-sponsored enterprises		102,940		—		(11,898)		91,042		106,534		—		(12,978)		93,556
Commercial - Government agency		30,675		—		(6,381)		24,294		30,544		—		(5,229)		25,315
Commercial - Government-sponsored enterprises		1,137,157		196		(129,963)		1,007,390		1,150,449		—		(138,451)		1,011,998
Collateralized mortgage obligations:
Government agency		1,036,671		—		(119,506)		917,165		1,080,492		—		(122,378)		958,114
Government-sponsored enterprises		1,720,672		—		(198,450)		1,522,222		1,798,178		—		(207,045)		1,591,133
Debt securities issued by states and political subdivisions		54,007		—		(5,986)		48,021		53,822		—		(7,768)		46,054
Total held-to-maturity securities	$	4,180,408	$	196	$	(483,343)	$	3,697,261	$	4,320,639	$	—	$	(505,817)	$	3,814,822

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

	June 30, 2023
	Amortized		Fair
(dollars in thousands)	Cost		Value
Available-for-sale securities
Due in one year or less	$	44,820	$	44,242
Due after one year through five years		60,590		57,478
Due after five years through ten years		175,172		162,622
Due after ten years		164,865		158,776
		445,447		423,118
Mortgage-backed securities:
Residential - Government agency		63,486		57,202
Residential - Government-sponsored enterprises		1,229,375		1,082,992
Commercial - Government agency		276,365		225,462
Commercial - Government-sponsored enterprises		96,441		87,897
Total mortgage-backed securities		1,665,667		1,453,553
Collateralized mortgage obligations:
Government agency		688,844		605,221
Government-sponsored enterprises		496,867		427,480
Total collateralized mortgage obligations		1,185,711		1,032,701
Total available-for-sale securities	$	3,296,825	$	2,909,372
Held-to-maturity securities
Due in one year or less	$	—	$	—
Due after one year through five years		—		—
Due after five years through ten years		10,255		9,264
Due after ten years		96,941		86,271
		107,196		95,535
Mortgage-backed securities:
Residential - Government agency		45,097		39,613
Residential - Government-sponsored enterprises		102,940		91,042
Commercial - Government agency		30,675		24,294
Commercial - Government-sponsored enterprises		1,137,157		1,007,390
Total mortgage-backed securities		1,315,869		1,162,339
Collateralized mortgage obligations:
Government agency		1,036,671		917,165
Government-sponsored enterprises		1,720,672		1,522,222
Total collateralized mortgage obligations		2,757,343		2,439,387
Total held-to-maturity securities	$	4,180,408	$	3,697,261

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

	Time in Continuous Loss as of June 30, 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	$	(708)	$	19,255	$	(11,001)	$	97,630	$	(11,709)	$	116,885
Government-sponsored enterprises debt securities		(760)		44,240		—		—		(760)		44,240
Mortgage-backed securities:
Residential - Government agency		—		—		(6,284)		57,202		(6,284)		57,202
Residential - Government-sponsored enterprises		(8,831)		165,828		(137,552)		917,164		(146,383)		1,082,992
Commercial - Government agency		(104)		4,256		(50,799)		221,206		(50,903)		225,462
Commercial - Government-sponsored enterprises		(546)		15,738		(7,998)		72,159		(8,544)		87,897
Commercial - Non-agency		(585)		21,379		—		—		(585)		21,379
Collateralized mortgage obligations:
Government agency		(1,260)		31,225		(82,363)		573,996		(83,623)		605,221
Government-sponsored enterprises		(2,894)		36,881		(66,493)		390,599		(69,387)		427,480
Collateralized loan obligations		(6,360)		163,538		(2,915)		77,076		(9,275)		240,614
Total available-for-sale securities with unrealized losses	$	(22,048)	$	502,340	$	(365,405)	$	2,407,032	$	(387,453)	$	2,909,372

	Time in Continuous Loss as of December 31, 2022
	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	$	(2,962)	$	83,870	$	(9,365)	$	67,112	$	(12,327)	$	150,982
Government-sponsored enterprises debt securities		(699)		44,301		—		—		(699)		44,301
Mortgage-backed securities:
Residential - Government agency		(7,069)		59,723		—		—		(7,069)		59,723
Residential - Government-sponsored enterprises		(73,954)		645,338		(83,309)		515,117		(157,263)		1,160,455
Commercial - Government agency		(15,852)		108,842		(28,995)		129,011		(44,847)		237,853
Commercial - Government-sponsored enterprises		(7,348)		94,657		(3,691)		24,916		(11,039)		119,573
Commercial - Non-agency		(493)		21,471		—		—		(493)		21,471
Collateralized mortgage obligations:
Government agency		(74,797)		596,907		(10,405)		56,415		(85,202)		653,322
Government-sponsored enterprises		(21,916)		198,108		(49,055)		264,024		(70,971)		462,132
Collateralized loan obligations:		(8,606)		170,042		—		—		(8,606)		170,042
Total available-for-sale securities with unrealized losses	$	(213,696)	$	2,023,259	$	(184,820)	$	1,056,595	$	(398,516)	$	3,079,854