Investment Securities (Tables)

3 Months Ended

Mar. 31, 2023

Investment Securities

Schedule of amortized cost and fair value of securities

	March 31, 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	$	130,936	$	—	$	(10,708)	$	120,228	$	163,309	$	—	$	(12,327)	$	150,982
Government-sponsored enterprises debt securities		45,000		—		(675)		44,325		45,000		—		(699)		44,301
Mortgage-backed securities:
Residential - Government agency		65,261		—		(5,964)		59,297		66,792		—		(7,069)		59,723
Residential - Government-sponsored enterprises		1,276,130		—		(143,876)		1,132,254		1,317,718		—		(157,263)		1,160,455
Commercial - Government agency		281,009		—		(45,938)		235,071		282,700		—		(44,847)		237,853
Commercial - Government-sponsored enterprises		126,057		—		(9,290)		116,767		130,612		—		(11,039)		119,573
Commercial - Non-agency		21,964		—		(831)		21,133		21,964		—		(493)		21,471
Collateralized mortgage obligations:
Government agency		715,004		—		(78,402)		636,602		738,524		—		(85,202)		653,322
Government-sponsored enterprises		516,458		—		(65,266)		451,192		533,103		—		(70,971)		462,132
Collateralized loan obligations		249,889		—		(12,478)		237,411		249,877		50		(8,606)		241,321
Total available-for-sale securities	$	3,427,708	$	—	$	(373,428)	$	3,054,280	$	3,549,599	$	50	$	(398,516)	$	3,151,133
Government agency debt securities	$	54,386	$	—	$	(4,694)	$	49,692	$	54,318	$	—	$	(5,674)	$	48,644
Mortgage-backed securities:
Residential - Government agency		45,860		—		(5,716)		40,144		46,302		—		(6,294)		40,008
Residential - Government-sponsored enterprises		104,868		—		(11,607)		93,261		106,534		—		(12,978)		93,556
Commercial - Government agency		30,606		—		(5,544)		25,062		30,544		—		(5,229)		25,315
Commercial - Government-sponsored enterprises		1,147,009		111		(117,007)		1,030,113		1,150,449		—		(138,451)		1,011,998
Collateralized mortgage obligations:
Government agency		1,060,910		—		(104,573)		956,337		1,080,492		—		(122,378)		958,114
Government-sponsored enterprises		1,763,805		—		(181,013)		1,582,792		1,798,178		—		(207,045)		1,591,133
Debt securities issued by states and political subdivisions		53,917		—		(6,840)		47,077		53,822		—		(7,768)		46,054
Total held-to-maturity securities	$	4,261,361	$	111	$	(436,994)	$	3,824,478	$	4,320,639	$	—	$	(505,817)	$	3,814,822

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

	March 31, 2023
	Amortized		Fair
(dollars in thousands)	Cost		Value
Available-for-sale securities
Due in one year or less	$	44,758	$	44,068
Due after one year through five years		60,529		57,863
Due after five years through ten years		177,638		165,278
Due after ten years		164,864		155,888
		447,789		423,097
Mortgage-backed securities:
Residential - Government agency		65,261		59,297
Residential - Government-sponsored enterprises		1,276,130		1,132,254
Commercial - Government agency		281,009		235,071
Commercial - Government-sponsored enterprises		126,057		116,767
Total mortgage-backed securities		1,748,457		1,543,389
Collateralized mortgage obligations:
Government agency		715,004		636,602
Government-sponsored enterprises		516,458		451,192
Total collateralized mortgage obligations		1,231,462		1,087,794
Total available-for-sale securities	$	3,427,708	$	3,054,280
Held-to-maturity securities
Due in one year or less	$	—	$	—
Due after one year through five years		—		—
Due after five years through ten years		10,232		9,141
Due after ten years		98,071		87,628
		108,303		96,769
Mortgage-backed securities:
Residential - Government agency		45,860		40,144
Residential - Government-sponsored enterprises		104,868		93,261
Commercial - Government agency		30,606		25,062
Commercial - Government-sponsored enterprises		1,147,009		1,030,113
Total mortgage-backed securities		1,328,343		1,188,580
Collateralized mortgage obligations:
Government agency		1,060,910		956,337
Government-sponsored enterprises		1,763,805		1,582,792
Total collateralized mortgage obligations		2,824,715		2,539,129
Total held-to-maturity securities	$	4,261,361	$	3,824,478

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

	Time in Continuous Loss as of March 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	$	(505)	$	19,453	$	(10,203)	$	100,775	$	(10,708)	$	120,228
Government-sponsored enterprises debt securities		(675)		44,325		—		—		(675)		44,325
Mortgage-backed securities:
Residential - Government agency		—		—		(5,964)		59,297		(5,964)		59,297
Residential - Government-sponsored enterprises		(7,523)		176,840		(136,353)		955,414		(143,876)		1,132,254
Commercial - Government agency		(90)		4,453		(45,848)		230,618		(45,938)		235,071
Commercial - Government-sponsored enterprises		(1,647)		43,342		(7,643)		73,425		(9,290)		116,767
Commercial - Non-agency		(831)		21,133		—		—		(831)		21,133
Collateralized mortgage obligations:
Government agency		(1,047)		33,970		(77,355)		602,632		(78,402)		636,602
Government-sponsored enterprises		(2,445)		38,871		(62,821)		412,321		(65,266)		451,192
Collateralized loan obligations		(7,764)		155,133		(4,714)		75,278		(12,478)		230,411
Total available-for-sale securities with unrealized losses	$	(22,527)	$	537,520	$	(350,901)	$	2,509,760	$	(373,428)	$	3,047,280

	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