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Note 3 - Investment Securities (Tables)

3 Months Ended

Mar. 31, 2025

Notes Tables

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

		At March 31, 2025
						Gross				Gross
		Amortized				Unrealized				Unrealized				Fair
		Cost				Gains				Losses				Value
		(In thousands)
Debt securities available for sale:
Agency residential mortgage-backed securities ("MBS")		$	218,825			$	4			$	(14,487	)		$	204,342
Agency commercial MBS			46,057				451				(6	)			46,502
Securities of U.S. Government sponsored entities			311,809				19				(12,106	)			299,722
Obligations of states and political subdivisions			62,177				7				(1,603	)			60,581
Corporate securities			1,967,432				-				(164,641	)			1,802,791
Collateralized loan obligations			823,921				514				(2,324	)			822,111
Total debt securities available for sale			3,430,221				995				(195,167	)			3,236,049
Debt securities held to maturity:
Agency residential MBS			53,528				23				(3,418	)			50,133
Obligations of states and political subdivisions			48,675				12				(203	)			48,484
Corporate securities			737,146				277				(22,915	)			714,508
Total debt securities held to maturity			839,349				312				(26,536	)			813,125
Total		$	4,269,570			$	1,307			$	(221,703	)		$	4,049,174

		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 March 31, 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		$	83,272			$	82,874			$	18,877			$	18,819
Over 1 to 5 years			1,093,030				1,039,910				379,408				376,571
Over 5 to 10 years			1,165,116				1,040,310				387,536				367,602
Subtotal			2,341,418				2,163,094				785,821				762,992
Collateralized loan obligations			823,921				822,111				-				-
Agency residential MBS			218,825				204,342				53,528				50,133
Agency commercial MBS			46,057				46,502				-				-
Total		$	3,430,221			$	3,236,049			$	839,349			$	813,125

		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 March 31, 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			10			$	13,725			$	(420	)			102			$	186,156			$	(14,067	)			112			$	199,881			$	(14,487	)
Agency commercial MBS			1				3,220				(6	)			-				-				-				1				3,220				(6	)
Securities of U.S. Government sponsored entities			1				1,937				(1	)			19				282,994				(12,105	)			20				284,931				(12,106	)
Obligations of states and political subdivisions			4				4,668				(17	)			39				49,171				(1,586	)			43				53,839				(1,603	)
Corporate securities			-				-				-				134				1,802,791				(164,641	)			134				1,802,791				(164,641	)
Collateralized loan obligations			3				38,770				(66	)			24				202,002				(2,258	)			27				240,772				(2,324	)
Total			19			$	62,320			$	(510	)			318			$	2,523,114			$	(194,657	)			337			$	2,585,434			$	(195,167	)

		Debt Securities Held to Maturity
		At March 31, 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			-			$	-			$	-				76			$	49,121			$	(3,418	)			76			$	49,121			$	(3,418	)
Obligations of states and political subdivisions			13				8,648				(19	)			27				24,879				(184	)			40				33,527				(203	)
Corporate securities			18				167,402				(1,597	)			35				459,147				(21,318	)			53				626,549				(22,915	)
Total			31			$	176,050			$	(1,616	)			138			$	533,147			$	(24,920	)			169			$	709,197			$	(26,536	)

		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 Three Months Ended March 31,
		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 March 31, 2025
		AAA/AA/A				BBB+/BBB				Not Rated				Total
		(In thousands)
Agency residential MBS		$	53,064			$	-			$	464			$	53,528
Obligations of states and political subdivisions			48,675				-				-				48,675
Corporate securities			554,871				182,275				-				737,146
Total		$	656,610			$	182,275			$	464			$	839,349

Interest Income from Investments [Table Text Block]

		For the Three Months
		Ended March 31,
		2025				2024
		(In thousands)
Taxable		$	41,280			$	54,145
Tax-exempt from regular federal income tax			839				994
Total interest income from investment securities		$	42,119			$	55,139

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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