Note 3 - Investment Securities (Tables)

6 Months Ended

Jun. 30, 2025

Notes Tables

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

		At June 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")		$	208,198			$	1			$	(12,921	)		$	195,278
Agency commercial MBS			95,966				364				(65	)			96,265
Securities of U.S. Government sponsored entities			312,417				27				(10,541	)			301,903
Obligations of states and political subdivisions			61,987				8				(1,160	)			60,835
Corporate securities			1,931,579				-				(139,558	)			1,792,021
Collateralized loan obligations			782,050				385				(2,288	)			780,147
Total debt securities available for sale			3,392,197				785				(166,533	)			3,226,449
Debt securities held to maturity:
Agency residential MBS			49,878				23				(2,887	)			47,014
Obligations of states and political subdivisions			45,716				8				(131	)			45,593
Corporate securities			738,846				1,162				(14,896	)			725,112
Total debt securities held to maturity			834,440				1,193				(17,914	)			817,719
Total		$	4,226,637			$	1,978			$	(184,447	)		$	4,044,168

		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 June 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		$	126,847			$	126,010			$	26,288			$	26,218
Over 1 to 5 years			1,207,932				1,150,997				400,042				399,891
Over 5 to 10 years			971,204				877,752				358,232				344,596
Subtotal			2,305,983				2,154,759				784,562				770,705
Collateralized loan obligations			782,050				780,147				-				-
Agency residential MBS			208,198				195,278				49,878				47,014
Agency commercial MBS			95,966				96,265				-				-
Total		$	3,392,197			$	3,226,449			$	834,440			$	817,719

		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 June 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			9			$	17,873			$	(549	)			102			$	177,288			$	(12,372	)			111			$	195,161			$	(12,921	)
Agency commercial MBS			6				26,624				(65	)			-				-				-				6				26,624				(65	)
Securities of U.S. Government sponsored entities			2				6,512				(2	)			19				285,159				(10,539	)			21				291,671				(10,541	)
Obligations of states and political subdivisions			4				4,649				(15	)			39				49,443				(1,145	)			43				54,092				(1,160	)
Corporate securities			-				-				-				132				1,792,021				(139,558	)			132				1,792,021				(139,558	)
Collateralized loan obligations			7				93,767				(191	)			22				187,138				(2,097	)			29				280,905				(2,288	)
Total			28			$	149,425			$	(822	)			314			$	2,491,049			$	(165,711	)			342			$	2,640,474			$	(166,533	)

		Debt Securities Held to Maturity
		At June 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			-			$	-			$	-				69			$	46,038			$	(2,887	)			69			$	46,038			$	(2,887	)
Obligations of states and political subdivisions			11				8,534				(8	)			24				22,673				(123	)			35				31,207				(131	)
Corporate securities			10				51,063				(234	)			34				452,940				(14,662	)			44				504,003				(14,896	)
Total			21			$	59,597			$	(242	)			127			$	521,651			$	(17,672	)			148			$	581,248			$	(17,914	)

		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 Six Months Ended June 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 June 30, 2025
		AAA/AA/A				BBB+/BBB				Not Rated				Total
		(In thousands)
Agency residential MBS		$	49,423			$	-			$	455			$	49,878
Obligations of states and political subdivisions			45,716				-				-				45,716
Corporate securities			556,117				182,729				-				738,846
Total		$	651,256			$	182,729			$	455			$	834,440

Interest Income from Investments [Table Text Block]

		For the Three Months								For the Six Months
		Ended June 30,
		2025				2024				2025				2024
		(In thousands)

Taxable		$	38,847			$	51,804			$	80,127			$	105,949
Tax-exempt from regular federal income tax			824				953				1,663				1,947
Total interest income from investment securities		$	39,671			$	52,757			$	81,790			$	107,896