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

3 Months Ended

Mar. 31, 2026

Notes Tables

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

		At March 31, 2026
						Gross				Gross
		Amortized				Unrealized				Unrealized				Fair
		Cost				Gains				Losses				Value
		(In thousands)
Debt securities available for sale:
Agency residential mortgage-backed securities ("MBS")		$	187,993			$	3			$	(10,688	)		$	177,308
Agency commercial MBS			955,794				884				(10,564	)			946,114
Securities of U.S. Government sponsored entities			307,683				26				(9,207	)			298,502
Obligations of states and political subdivisions			46,118				6				(702	)			45,422
Corporate securities			1,957,629				9				(122,116	)			1,835,522
Collateralized loan obligations			293,927				351				(291	)			293,987
Total debt securities available for sale			3,749,144				1,279				(153,568	)			3,596,855
Debt securities held to maturity:
Agency residential MBS			41,271				23				(2,311	)			38,983
Obligations of states and political subdivisions			26,120				10				(16	)			26,114
Corporate securities			732,168				700				(13,661	)			719,207
Total debt securities held to maturity			799,559				733				(15,988	)			784,304
Total		$	4,548,703			$	2,012			$	(169,556	)		$	4,381,159

		At December 31, 2025
						Gross				Gross
		Amortized				Unrealized				Unrealized				Fair
		Cost				Gains				Losses				Value
		(In thousands)
Debt securities available for sale:
Agency residential MBS		$	194,394			$	8			$	(10,056	)		$	184,346
Agency commercial MBS			709,371				1,600				(3,411	)			707,560
Securities of U.S. Government sponsored entities			309,079				72				(6,739	)			302,412
Obligations of states and political subdivisions			46,264				1				(543	)			45,722
Corporate securities			1,913,553				-				(109,473	)			1,804,080
Collateralized loan obligations			425,465				400				(1,251	)			424,614
Total debt securities available for sale			3,598,126				2,081				(131,473	)			3,468,734
Debt securities held to maturity:
Agency residential MBS			43,734				26				(2,231	)			41,529
Obligations of states and political subdivisions			33,597				10				(36	)			33,571
Corporate securities			742,244				3,245				(8,009	)			737,480
Total debt securities held to maturity			819,575				3,281				(10,276	)			812,580
Total		$	4,417,701			$	5,362			$	(141,749	)		$	4,281,314

Investments Classified by Contractual Maturity Date [Table Text Block]

		At March 31, 2026
		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		$	204,192			$	203,356			$	60,501			$	60,400
Over 1 to 5 years			1,435,262				1,360,107				412,457				410,862
Over 5 to 10 years			671,976				615,983				285,330				274,059
Subtotal			2,311,430				2,179,446				758,288				745,321
Collateralized loan obligations			293,927				293,987				-				-
Agency residential MBS			187,993				177,308				41,271				38,983
Agency commercial MBS			955,794				946,114				-				-
Total		$	3,749,144			$	3,596,855			$	799,559			$	784,304

		At December 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		$	199,254			$	198,573			$	33,326			$	33,302
Over 1 to 5 years			1,231,338				1,182,101				425,387				428,326
Over 5 to 10 years			838,304				771,540				317,128				309,423
Subtotal			2,268,896				2,152,214				775,841				771,051
Collateralized loan obligations			425,465				424,614				-				-
Agency residential MBS			194,394				184,346				43,734				41,529
Agency commercial MBS			709,371				707,560				-				-
Total		$	3,598,126			$	3,468,734			$	819,575			$	812,580

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

		Debt Securities Available for Sale
		At March 31, 2026
		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			4			$	13,297			$	(204	)			104			$	163,509			$	(10,484	)			108			$	176,806			$	(10,688	)
Agency commercial MBS			99				809,211				(10,564	)			-				-				-				99				809,211				(10,564	)
Securities of U.S. Government sponsored entities			1				5,351				(30	)			18				282,938				(9,177	)			19				288,289				(9,207	)
Obligations of states and political subdivisions			2				4,201				(23	)			28				36,135				(679	)			30				40,336				(702	)
Corporate securities			12				78,980				(777	)			124				1,746,543				(121,339	)			136				1,825,523				(122,116	)
Collateralized loan obligations			2				22,924				(76	)			2				10,740				(215	)			4				33,664				(291	)
Total			120			$	933,964			$	(11,674	)			276			$	2,239,865			$	(141,894	)			396			$	3,173,829			$	(153,568	)

		Debt Securities Held to Maturity
		At March 31, 2026
		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			-			$	-			$	-				54			$	38,020			$	(2,311	)			54			$	38,020			$	(2,311	)
Obligations of states and political subdivisions			1				624				(1	)			10				9,344				(15	)			11				9,968				(16	)
Corporate securities			24				226,589				(916	)			23				355,425				(12,745	)			47				582,014				(13,661	)
Total			25			$	227,213			$	(917	)			87			$	402,789			$	(15,071	)			112			$	630,002			$	(15,988	)

		Debt Securities Available for Sale
		At December 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			2			$	10,541			$	(147	)			107			$	173,186			$	(9,909	)			109			$	183,727			$	(10,056	)
Agency commercial MBS			56				438,102				(3,411	)			-				-				-				56				438,102				(3,411	)
Securities of U.S. Government sponsored entities			-				-				-				19				284,747				(6,739	)			19				284,747				(6,739	)
Obligations of states and political subdivisions			2				3,382				(1	)			28				37,520				(542	)			30				40,902				(543	)
Corporate securities			-				-				-				129				1,804,080				(109,473	)			129				1,804,080				(109,473	)
Collateralized loan obligations			2				22,924				(77	)			5				49,693				(1,174	)			7				72,617				(1,251	)
Total			62			$	474,949			$	(3,636	)			288			$	2,349,226			$	(127,837	)			350			$	2,824,175			$	(131,473	)

		Debt Securities Held to Maturity
		At December 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			-			$	-			$	-				59			$	40,523			$	(2,231	)			59			$	40,523			$	(2,231	)
Obligations of states and political subdivisions			-				-				-				17				16,087				(36	)			17				16,087				(36	)
Corporate securities			-				-				-				23				359,421				(8,009	)			23				359,421				(8,009	)
Total			-			$	-			$	-				99			$	416,031			$	(10,276	)			99			$	416,031			$	(10,276	)

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

		For the Three Months Ended March 31,
		2026				2025
		(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, 2026
		AAA/AA/A				BBB+/BBB				Not Rated				Total
		(In thousands)
Agency residential MBS		$	40,840			$	-			$	431			$	41,271
Obligations of states and political subdivisions			26,120				-				-				26,120
Corporate securities			578,078				154,090				-				732,168
Total		$	645,038			$	154,090			$	431			$	799,559

Interest Income from Investments [Table Text Block]

		For the Three Months
		Ended March 31,
		2026				2025
		(In thousands)

Taxable		$	41,029			$	41,280
Tax-exempt from regular federal income tax			606				839
Total interest income from investment securities		$	41,635			$	42,119