Investment Securities (Tables)

9 Months Ended

Sep. 30, 2023

Investment Securities

Schedule of amortized cost and fair value of securities

	September 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	$	126,264	$	—	$	(12,105)	$	114,159	$	163,309	$	—	$	(12,327)	$	150,982
Government-sponsored enterprises debt securities		20,000		—		(740)		19,260		45,000		—		(699)		44,301
Mortgage-backed securities:
Residential - Government agency		61,768		—		(9,406)		52,362		66,792		—		(7,069)		59,723
Residential - Government-sponsored enterprises		1,185,269		—		(179,487)		1,005,782		1,317,718		—		(157,263)		1,160,455
Commercial - Government agency		272,432		—		(60,535)		211,897		282,700		—		(44,847)		237,853
Commercial - Government-sponsored enterprises		94,021		—		(9,101)		84,920		130,612		—		(11,039)		119,573
Commercial - Non-agency		21,964		—		(362)		21,602		21,964		—		(493)		21,471
Collateralized mortgage obligations:
Government agency		661,207		—		(95,355)		565,852		738,524		—		(85,202)		653,322
Government-sponsored enterprises		479,217		—		(78,469)		400,748		533,103		—		(70,971)		462,132
Collateralized loan obligations		249,889		21		(3,788)		246,122		249,877		50		(8,606)		241,321
Total available-for-sale securities	$	3,172,031	$	21	$	(449,348)	$	2,722,704	$	3,549,599	$	50	$	(398,516)	$	3,151,133
Government agency debt securities	$	53,105	$	—	$	(7,901)	$	45,204	$	54,318	$	—	$	(5,674)	$	48,644
Mortgage-backed securities:
Residential - Government agency		44,379		—		(8,024)		36,355		46,302		—		(6,294)		40,008
Residential - Government-sponsored enterprises		100,905		—		(18,151)		82,754		106,534		—		(12,978)		93,556
Commercial - Government agency		30,733		—		(8,756)		21,977		30,544		—		(5,229)		25,315
Commercial - Government-sponsored enterprises		1,132,818		153		(194,471)		938,500		1,150,449		—		(138,451)		1,011,998
Collateralized mortgage obligations:
Government agency		1,010,551		—		(153,260)		857,291		1,080,492		—		(122,378)		958,114
Government-sponsored enterprises		1,677,519		—		(271,248)		1,406,271		1,798,178		—		(207,045)		1,591,133
Debt securities issued by states and political subdivisions		54,104		—		(9,427)		44,677		53,822		—		(7,768)		46,054
Total held-to-maturity securities	$	4,104,114	$	153	$	(671,238)	$	3,433,029	$	4,320,639	$	—	$	(505,817)	$	3,814,822

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

	September 30, 2023
	Amortized		Fair
(dollars in thousands)	Cost		Value
Available-for-sale securities
Due in one year or less	$	19,884	$	19,534
Due after one year through five years		60,651		57,469
Due after five years through ten years		172,717		161,989
Due after ten years		164,865		162,151
		418,117		401,143
Mortgage-backed securities:
Residential - Government agency		61,768		52,362
Residential - Government-sponsored enterprises		1,185,269		1,005,782
Commercial - Government agency		272,432		211,897
Commercial - Government-sponsored enterprises		94,021		84,920
Total mortgage-backed securities		1,613,490		1,354,961
Collateralized mortgage obligations:
Government agency		661,207		565,852
Government-sponsored enterprises		479,217		400,748
Total collateralized mortgage obligations		1,140,424		966,600
Total available-for-sale securities	$	3,172,031	$	2,722,704
Held-to-maturity securities
Due in one year or less	$	—	$	—
Due after one year through five years		—		—
Due after five years through ten years		10,280		8,732
Due after ten years		96,929		81,149
		107,209		89,881
Mortgage-backed securities:
Residential - Government agency		44,379		36,355
Residential - Government-sponsored enterprises		100,905		82,754
Commercial - Government agency		30,733		21,977
Commercial - Government-sponsored enterprises		1,132,818		938,500
Total mortgage-backed securities		1,308,835		1,079,586
Collateralized mortgage obligations:
Government agency		1,010,551		857,291
Government-sponsored enterprises		1,677,519		1,406,271
Total collateralized mortgage obligations		2,688,070		2,263,562
Total held-to-maturity securities	$	4,104,114	$	3,433,029

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

	Time in Continuous Loss as of September 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	$	—	$	—	$	(12,105)	$	114,159	$	(12,105)	$	114,159
Government-sponsored enterprises debt securities		—		—		(740)		19,260		(740)		19,260
Mortgage-backed securities:
Residential - Government agency		—		—		(9,406)		52,362		(9,406)		52,362
Residential - Government-sponsored enterprises		—		—		(179,487)		1,005,782		(179,487)		1,005,782
Commercial - Government agency		—		—		(60,535)		211,897		(60,535)		211,897
Commercial - Government-sponsored enterprises		—		—		(9,101)		84,920		(9,101)		84,920
Commercial - Non-agency		—		—		(362)		21,602		(362)		21,602
Collateralized mortgage obligations:
Government agency		—		—		(95,355)		565,852		(95,355)		565,852
Government-sponsored enterprises		—		—		(78,469)		400,748		(78,469)		400,748
Collateralized loan obligations		(973)		75,258		(2,815)		169,131		(3,788)		244,389
Total available-for-sale securities with unrealized losses	$	(973)	$	75,258	$	(448,375)	$	2,645,713	$	(449,348)	$	2,720,971

	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