Securities (Tables)

3 Months Ended

Mar. 31, 2022

Securities

Schedule of amortized cost and fair value of investment securities held to maturity

			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
(Dollars in thousands)	Cost		Gains		Losses		Value
March 31, 2022:
U.S. Government agencies	$	197,259	$	—	$	(12,318)	$	184,941
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		1,740,217		—		(125,037)		1,615,180
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		455,180		—		(24,951)		430,229
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		373,100		108		(28,673)		344,535
Small Business Administration loan-backed securities		62,013		—		(6,403)		55,610
	$	2,827,769	$	108	$	(197,382)	$	2,630,495
December 31, 2021:
U.S. Government agencies	$	112,913	$	—	$	(2,627)	$	110,286
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		1,120,104		14		(24,278)		1,095,840
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		174,178		—		(4,937)		169,241
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		350,116		304		(8,021)		342,399
Small Business Administration loan-backed securities		62,590		—		(2,292)		60,298
	$	1,819,901	$	318	$	(42,155)	$	1,778,064

Schedule of amortized cost and fair value of investment securities available for sale

			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
(Dollars in thousands)	Cost		Gains		Losses		Value
March 31, 2022:
U.S. Treasuries	$	270,547	$	—	$	(1,966)	$	268,581
U.S. Government agencies		190,899		—		(10,957)		179,942
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		2,156,635		48		(142,779)		2,013,904
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		739,068		167		(44,530)		694,705
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		1,247,034		301		(95,475)		1,151,860
State and municipal obligations		1,201,639		1,884		(75,826)		1,127,697
Small Business Administration loan-backed securities		477,702		551		(20,896)		457,357
Corporate securities		30,619		34		(493)		30,160
	$	6,314,143	$	2,985	$	(392,922)	$	5,924,206
December 31, 2021:
U.S. Government agencies	$	98,882	$	—	$	(1,765)	$	97,117
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		1,851,700		5,324		(25,985)		1,831,039
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		730,949		5,957		(10,911)		725,995
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		1,220,233		5,438		(18,430)		1,207,241
State and municipal obligations		798,211		16,697		(2,219)		812,689
Small Business Administration loan-backed securities		502,812		2,330		(4,479)		500,663
Corporate securities		18,509		234		(9)		18,734
	$	5,221,296	$	35,980	$	(63,798)	$	5,193,478

Schedule of amortized cost and carrying value of other investment securities

	Carrying
(Dollars in thousands)	Value
March 31, 2022:
Federal Home Loan Bank stock	$	15,095
Federal Reserve Bank stock		149,659
Investment in unconsolidated subsidiaries		3,563
Other nonmarketable investment securities		10,941
	$	179,258
December 31, 2021:
Federal Home Loan Bank stock	$	16,283
Federal Reserve Bank stock		129,716
Investment in unconsolidated subsidiaries		3,563
Other nonmarketable investment securities		11,006
	$	160,568

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

	Securities				Securities
	Held to Maturity				Available for Sale
	Amortized		Fair		Amortized		Fair
(Dollars in thousands)	Cost		Value		Cost		Value
Due in one year or less	$	—	$	—	$	7,567	$	7,590
Due after one year through five years		64,365		64,002		477,415		471,472
Due after five years through ten years		433,463		411,807		1,098,144		1,034,518
Due after ten years		2,329,941		2,154,686		4,731,017		4,410,626
	$	2,827,769	$	2,630,495	$	6,314,143	$	5,924,206

Schedule of securities with gross unrealized losses, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position

	Less Than				Twelve Months
	Twelve Months				or More
	Gross Unrealized		Fair		Gross Unrealized		Fair
(Dollars in thousands)	Losses		Value		Losses		Value
March 31, 2022:
Securities Held to Maturity
U.S. Government agencies	$	6,624	$	140,646	$	5,694	$	44,295
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		67,934		1,058,367		57,103		556,812
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		17,920		273,429		7,031		55,589
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		13,930		140,104		14,743		129,759
Small Business Administration loan-backed securities		—		—		6,403		55,610
	$	106,408	$	1,612,546	$	90,974	$	842,065
Securities Available for Sale
U.S. Treasuries	$	1,966	$	268,581	$	—	$	—
U.S. Government agencies		8,124		157,776		2,833		22,166
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		98,405		1,607,878		44,374		398,080
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		32,801		562,732		11,729		90,910
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		79,666		876,459		15,809		171,206
State and municipal obligations		71,078		960,986		4,748		29,605
Small Business Administration loan-backed securities		13,526		247,135		7,370		141,086
Corporate securities		493		23,628		—		—
	$	306,059	$	4,705,175	$	86,863	$	853,053
December 31, 2021:
Securities Held to Maturity
U.S. Government agencies	$	1,745	$	86,168	$	882	$	24,118
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises	$	18,768		868,327		5,510		184,819
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		4,937		169,240		—		—
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		4,902		154,963		3,119		75,450
Small Business Administration loan-backed securities		1,281		37,408		1,011		22,890
	$	31,633	$	1,316,106	$	10,522	$	307,277
Securities Available for Sale
U.S. Government agencies	$	529	$	73,353	$	1,236	$	23,763
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		17,381		1,274,934		8,604		221,435
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		10,911		432,300		—		—
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		13,120		846,581		5,310		98,106
State and municipal obligations		1,867		123,987		352		8,579
Small Business Administration loan-backed securities		2,720		179,168		1,759		110,309
Corporate securities		9		4,991		—		—
	$	46,537	$	2,935,314	$	17,261	$	462,192

Schedule of trading securities

	March 31,		December 31,
(Dollars in thousands)	2022		2021
U.S. Government agencies	$	14,801	$	5,154
Residential mortgage pass-through securities issued or guaranteed by U.S.
government agencies or sponsored enterprises		26,484		6,853
Other residential mortgage issued or guaranteed by U.S. government
agencies or sponsored enterprises		7,634		12,315
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		10,973		29,667
State and municipal obligations		12,078		20,798
Other debt securities		2,264		2,902
	$	74,234	$	77,689

Summary of net gains and losses on trading securities

	Three Months Ended March 31,
(Dollars in thousands)	2022		2021
Net (losses) gain on sales transaction	$	(1,239)	$	119
Net mark to mark losses		(1,976)		(726)
Net losses on trading securities	$	(3,215)	$	(607)