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Note 3 - Debt Securities Available for Sale and Held to Maturity (Tables)

9 Months Ended

Sep. 30, 2025

Notes Tables

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

		At September 30, 2025
						Gross				Gross
		Amortized				Unrealized				Unrealized				Fair
		Cost				Gains				Losses				Value
		(In thousands)
Debt securities available for sale:
Agency residential mortgage-backed securities ("MBS")		$	203,929			$	6			$	(11,445	)		$	192,490
Agency commercial MBS			398,586				788				(2,210	)			397,164
Securities of U.S. Government sponsored entities			313,025				55				(7,888	)			305,192
Obligations of states and political subdivisions			52,418				8				(573	)			51,853
Corporate securities			1,917,181				-				(119,619	)			1,797,562
Collateralized loan obligations			562,034				512				(1,483	)			561,063
Total debt securities available for sale			3,447,173				1,369				(143,218	)			3,305,324
Debt securities held to maturity:
Agency residential MBS			46,433				26				(2,566	)			43,893
Obligations of states and political subdivisions			39,528				15				(45	)			39,498
Corporate securities			740,545				2,576				(9,324	)			733,797
Total debt securities held to maturity			826,506				2,617				(11,935	)			817,188
Total		$	4,273,679			$	3,986			$	(155,153	)		$	4,122,512

		At December 31, 2024
						Gross				Gross
		Amortized				Unrealized				Unrealized				Fair
		Cost				Gains				Losses				Value
		(In thousands)
Debt securities available for sale:
Agency residential MBS		$	229,050			$	1			$	(17,991	)		$	211,060
Agency commercial MBS			7,098				-				(132	)			6,966
Securities of U.S. Government sponsored entities			311,201				1				(19,085	)			292,117
U.S. Treasury securities			4,945				10				-				4,955
Obligations of states and political subdivisions			63,878				9				(1,701	)			62,186
Corporate securities			2,031,144				127				(195,334	)			1,835,937
Collateralized loan obligations			987,155				642				(5,208	)			982,589
Total debt securities available for sale			3,634,471				790				(239,451	)			3,395,810
Debt securities held to maturity:
Agency residential MBS			57,927				23				(4,218	)			53,732
Obligations of states and political subdivisions			51,261				12				(377	)			50,896
Corporate securities			735,447				-				(32,237	)			703,210
Total debt securities held to maturity			844,635				35				(36,832	)			807,838
Total		$	4,479,106			$	825			$	(276,283	)		$	4,203,648

Investments Classified by Contractual Maturity Date [Table Text Block]

		At September 30, 2025
		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		$	168,382			$	167,424			$	29,562			$	29,535
Over 1 to 5 years			1,234,938				1,183,538				411,838				413,990
Over 5 to 10 years			879,304				803,645				338,673				329,770
Subtotal			2,282,624				2,154,607				780,073				773,295
Collateralized loan obligations			562,034				561,063				-				-
Agency residential MBS			203,929				192,490				46,433				43,893
Agency commercial MBS			398,586				397,164				-				-
Total		$	3,447,173			$	3,305,324			$	826,506			$	817,188

		At December 31, 2024
		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		$	124,667			$	124,448			$	13,508			$	13,468
Over 1 to 5 years			993,874				940,578				347,566				342,500
Over 5 to 10 years			1,292,627				1,130,169				425,634				398,138
Subtotal			2,411,168				2,195,195				786,708				754,106
Collateralized loan obligations			987,155				982,589				-				-
Agency residential MBS			229,050				211,060				57,927				53,732
Agency commercial MBS			7,098				6,966				-				-
Total		$	3,634,471			$	3,395,810			$	844,635			$	807,838

Schedule of Unrealized Loss on Investments 1 [Table Text Block]

		Debt Securities Available for Sale
		At September 30, 2025
		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			5			$	18,550			$	(337	)			104			$	173,381			$	(11,108	)			109			$	191,931			$	(11,445	)
Agency commercial MBS			33				233,147				(2,210	)			-				-				-				33				233,147				(2,210	)
Securities of U.S. Government sponsored entities			-				-				-				19				288,409				(7,888	)			19				288,409				(7,888	)
Obligations of states and political subdivisions			1				1,311				(2	)			30				40,371				(571	)			31				41,682				(573	)
Corporate securities			-				-				-				129				1,796,562				(119,619	)			129				1,796,562				(119,619	)
Collateralized loan obligations			3				25,645				(78	)			9				84,308				(1,405	)			12				109,953				(1,483	)
Total			42			$	278,653			$	(2,627	)			291			$	2,383,031			$	(140,591	)			333			$	2,661,684			$	(143,218	)

		Debt Securities Held to Maturity
		At September 30, 2025
		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			-			$	-			$	-				63			$	42,819			$	(2,566	)			63			$	42,819			$	(2,566	)
Obligations of states and political subdivisions			1				365				-				20				18,465				(45	)			21				18,830				(45	)
Corporate securities			2				4,705				(9	)			27				373,660				(9,315	)			29				378,365				(9,324	)
Total			3			$	5,070			$	(9	)			110			$	434,944			$	(11,926	)			113			$	440,014			$	(11,935	)

		Debt Securities Available for Sale
		At December 31, 2024
		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			12			$	18,030			$	(471	)			103			$	192,963			$	(17,520	)			115			$	210,993			$	(17,991	)
Agency commercial MBS			2				6,966				(132	)			-				-				-				2				6,966				(132	)
Securities of U.S. Government sponsored entities			3				12,085				(53	)			19				275,467				(19,032	)			22				287,552				(19,085	)
Obligations of states and political subdivisions			2				2,764				(21	)			40				51,759				(1,680	)			42				54,523				(1,701	)
Corporate securities			-				-				-				138				1,824,327				(195,334	)			138				1,824,327				(195,334	)
Collateralized loan obligations			3				26,825				(15	)			32				309,249				(5,193	)			35				336,074				(5,208	)
Total			22			$	66,670			$	(692	)			332			$	2,653,765			$	(238,759	)			354			$	2,720,435			$	(239,451	)

		Debt Securities Held to Maturity
		At December 31, 2024
		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			-			$	-			$	-				80			$	52,771			$	(4,218	)			80			$	52,771			$	(4,218	)
Obligations of states and political subdivisions			24				15,822				(78	)			26				25,814				(299	)			50				41,636				(377	)
Corporate securities			23				251,790				(4,230	)			35				451,420				(28,007	)			58				703,210				(32,237	)
Total			47			$	267,612			$	(4,308	)			141			$	530,005			$	(32,524	)			188			$	797,617			$	(36,832	)

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

		For the Nine Months Ended September 30,
		2025				2024
		(In thousands)
Allowance for credit losses:
Beginning balance		$	1			$	1
Provision			-				-
Chargeoffs			-				-
Recoveries			-				-
Total ending balance		$	1			$	1

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

		Credit Risk Profile by Credit Rating
		At September 30, 2025
		AAA/AA/A				BBB+/BBB				Not Rated				Total
		(In thousands)
Agency residential MBS		$	45,984			$	-			$	449			$	46,433
Obligations of states and political subdivisions			39,528				-				-				39,528
Corporate securities			557,363				183,182				-				740,545
Total		$	642,875			$	183,182			$	449			$	826,506

Interest Income from Investments [Table Text Block]

		For the Three Months								For the Nine Months
		Ended September 30,
		2025				2024				2025				2024
		(In thousands)
Taxable		$	38,402			$	48,699			$	118,529			$	154,648
Tax-exempt from federal income tax			735				892				2,398				2,839
Total interest income from investment securities		$	39,137			$	49,591			$	120,927			$	157,487

X

- Definition

Tabular disclosure of allowance for credit loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
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