Note 3 - Investment Securities (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

Debt Securities, Available-for-sale and Held-to-maturity [Table Text Block]

	At March 31, 2022
			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(In thousands)
Debt securities available for sale
Agency residential mortgage-backed securities ("MBS")	$	369,329	$	1,219	$	(7,367	)	$	363,181
Securities of U.S. Government entities		111		-		(1	)		110
Obligations of states and political subdivisions		89,819		379		(603	)		89,595
Corporate securities		2,665,573		7,083		(125,538	)		2,547,118
Collateralized Loan Obligations		1,617,118		1,270		(1,804	)		1,616,584
Total debt securities available for sale		4,741,950		9,951		(135,313	)		4,616,588
Debt securities held to maturity
Agency residential MBS		133,754		76		(3,227	)		130,603
Obligations of states and political subdivisions		146,773		842		(31	)		147,584
Total debt securities held to maturity		280,527		918		(3,258	)		278,187
Total	$	5,022,477	$	10,869	$	(138,571	)	$	4,894,775

	At December 31, 2021
			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(In thousands)
Debt securities available for sale
Agency residential MBS	$	399,997	$	11,766	$	(37	)	$	411,726
Securities of U.S. Government entities		119		-		-			119
Obligations of states and political subdivisions		90,107		3,842		(29	)		93,920
Corporate securities		2,692,792		63,573		(9,630	)		2,746,735
Collateralized loan obligations		1,385,331		1,743		(719	)		1,386,355
Total debt securities available for sale		4,568,346		80,924		(10,415	)		4,638,855
Debt securities held to maturity
Agency residential MBS		148,390		3,114		(37	)		151,467
Obligations of states and political subdivisions		158,013		3,082		-			161,095
Total debt securities held to maturity		306,403		6,196		(37	)		312,562
Total	$	4,874,749	$	87,120	$	(10,452	)	$	4,951,417

Investments Classified by Contractual Maturity Date [Table Text Block]

	At March 31, 2022
	Securities Available				Securities Held
	for Sale				to Maturity
	Amortized		Fair		Amortized		Fair
	Cost		Value		Cost		Value
	(In thousands)
Maturity in years:
1 year or less	$	373,260	$	375,294	$	12,582	$	12,625
Over 1 to 5 years		600,734		603,365		122,239		122,862
Over 5 to 10 years		2,417,110		2,315,148		11,952		12,097
Over 10 years		981,517		959,600		-		-
Subtotal		4,372,621		4,253,407		146,773		147,584
MBS		369,329		363,181		133,754		130,603
Total	$	4,741,950	$	4,616,588	$	280,527	$	278,187

	At December 31, 2021
	Debt Securities Available				Debt Securities Held
	for Sale				to Maturity
	Amortized		Fair		Amortized		Fair
	Cost		Value		Cost		Value
	(In thousands)
Maturity in years:
1 year or less	$	306,333	$	309,257	$	15,836	$	15,941
Over 1 to 5 years		707,062		738,057		125,001		127,539
Over 5 to 10 years		2,320,559		2,347,242		17,176		17,615
Over 10 years		834,395		832,573		-		-
Subtotal		4,168,349		4,227,129		158,013		161,095
MBS		399,997		411,726		148,390		151,467
Total	$	4,568,346	$	4,638,855	$	306,403	$	312,562

Schedule of Unrealized Loss on Investments [Table Text Block]

	Debt Securities Available for Sale
	At March 31, 2022
	No. of		Less than 12 months					No. of		12 months or longer					No. of		Total
	Investment				Unrealized			Investment				Unrealized			Investment				Unrealized
	Positions		Fair Value		Losses			Positions		Fair Value		Losses			Positions		Fair Value		Losses
	($ in thousands)
Agency residential MBS		71	$	249,243	$	(7,367	)		2	$	44	$	-			73	$	249,287	$	(7,367	)
Securities of U.S. Government entities		-		-		-			1		110		(1	)		1		110		(1	)
Obligations of states and political subdivisions		41		40,199		(543	)		3		1,355		(60	)		44		41,554		(603	)
Corporate securities		118		1,705,961		(113,614	)		9		97,149		(11,924	)		127		1,803,110		(125,538	)
Collateralized loan obligations		25		258,640		(1,334	)		14		98,161		(470	)		39		356,801		(1,804	)
Total		255	$	2,254,043	$	(122,858	)		29	$	196,819	$	(12,455	)		284	$	2,450,862	$	(135,313	)

	Debt Securities Held to Maturity
	At March 31, 2022
	No. of		Less than 12 months					No. of		12 months or longer					No. of		Total
	Investment				Unrecognized			Investment				Unrecognized			Investment				Unrecognized
	Positions		Fair Value		Losses			Positions		Fair Value		Losses			Positions		Fair Value		Losses
	($ in thousands)
Agency residential MBS		70	$	122,639	$	(3,165	)		4	$	980	$	(62	)		74	$	123,619	$	(3,227	)
Obligations of states and political subdivisions		5		5,773		(31	)		-		-		-			5		5,773		(31	)
Total		75	$	128,412	$	(3,196	)		4	$	980	$	(62	)		79	$	129,392	$	(3,258	)

	Debt Securities Available for Sale
	At December 31, 2021
	No. of		Less than 12 months					No. of		12 months or longer					No. of		Total
	Investment				Unrealized			Investment				Unrealized			Investment				Unrealized
	Positions		Fair Value		Losses			Positions		Fair Value		Losses			Positions		Fair Value		Losses
	($ in thousands)
Agency residential MBS		7	$	8,900	$	(37	)		2	$	47	$	-			9	$	8,947	$	(37	)
Securities of U.S. Government entities		-		-		-			1		119		-			1		119		-
Obligations of states and political subdivisions		6		2,859		(27	)		2		669		(2	)		8		3,528		(29	)
Corporate securities		56		691,555		(9,630	)		-		-		-			56		691,555		(9,630	)
Collateralized loan obligations		19		208,199		(521	)		8		51,523		(198	)		27		259,722		(719	)
Total		88	$	911,513	$	(10,215	)		13	$	52,358	$	(200	)		101	$	963,871	$	(10,415	)

	Debt Securities Held to Maturity
	At December 31, 2021
	No. of		Less than 12 months					No. of		12 months or longer					No. of		Total
	Investment				Unrecognized			Investment				Unrecognized			Investment				Unrecognized
	Positions		Fair Value		Losses			Positions		Fair Value		Losses			Positions		Fair Value		Losses
	($ in thousands)
Agency residential MBS		1	$	542	$	(19	)		3	$	530	$	(18	)		4	$	1,072	$	(37	)

Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Table Text Block]

	For the Three Months Ended March 31,
	2022		2021
	(In thousands)
Allowance for credit losses:
Beginning balance	$	7	$	9
Provision		-		-
Chargeoffs		-		-
Recoveries		-		-
Total ending balance	$	7	$	9

Debt Securities, Held-to-Maturity, Credit Quality Indicator [Table Text Block]

	Credit Risk Profile by Credit Rating
	At March 31, 2022
	AAA/AA/A		B-		Not Rated		Total
	(In thousands)
Agency residential MBS	$	116	$	529	$	133,109	$	133,754
Obligations of states and political subdivisions		145,645		-		1,128		146,773
Total	$	145,761	$	529	$	134,237	$	280,527

Interest Income from Investments [Table Text Block]

	For the Three Months
	Ended March 31,
	2022		2021
	(In thousands)
Taxable	$	28,733	$	25,198
Tax-exempt from regular federal income tax		1,605		2,399
Total interest income from investment securities	$	30,338	$	27,597