Note 8 - Investment Securities (Tables)

9 Months Ended

Sep. 30, 2023

Notes Tables

Schedule of Available-for-Sale Securities Reconciliation [Table Text Block]

	September 30, 2023
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	392,956	$	41	$	155	$	392,842
U.S. government agency entities		51,018		144		161		51,001
U.S. government sponsored entities		33,709		—		89		33,620
Mortgage-backed securities		916,719		42		154,958		761,803
Collateralized mortgage obligations		32,015		—		4,317		27,698
Corporate debt securities		248,534		—		16,662		231,872
Foreign debt securities		10,000		—		38		9,962
Total	$	1,684,951	$	227	$	176,380	$	1,508,798

	December 31, 2022
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	241,611	$	—	$	1,111	$	240,500
U.S. government agency entities		63,347		384		121		63,610
U.S. government sponsored entities		30,000		—		—		30,000
Mortgage-backed securities		993,883		194		126,983		867,094
Collateralized mortgage obligations		34,552		—		3,491		31,061
Corporate debt securities		258,780		112		17,809		241,083
Total	$	1,622,173	$	690	$	149,515	$	1,473,348

Investments Classified by Contractual Maturity Date [Table Text Block]

	September 30, 2023
	Securities Available-For-Sale
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	442,957	$	442,208
Due after one year through five years		241,407		225,644
Due after five years through ten years		154,327		142,157
Due after ten years		846,260		698,789
Total	$	1,684,951	$	1,508,798

Schedule of Unrealized Loss on Investments [Table Text Block]

	September 30, 2023
	Less than 12 Months				12 Months or Longer				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	49,153	$	126	$	49,804	$	29	$	98,957	$	155
U.S. government agency entities		17,698		39		1,487		122		19,185		161
U.S. government sponsored entities		33,621		89		—		—		33,621		89
Mortgage-backed securities		17,695		642		743,568		154,316		761,263		154,958
Collateralized mortgage obligations		—		—		27,698		4,317		27,698		4,317
Corporate debt securities		68,285		1,715		163,586		14,947		231,871		16,662
Foreign debt securities		9,962		38		—		—		9,962		38
Total	$	196,414	$	2,649	$	986,143	$	173,731	$	1,182,557	$	176,380

	December 31, 2022
	Less than 12 Months				12 Months or Longer				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	240,500	$	1,111	$	—	$	—	$	240,500	$	1,111
U.S. government agency entities		—		—		1,806		121		1,806		121
Mortgage-backed securities		394,123		33,042		452,739		93,941		846,862		126,983
Collateralized mortgage obligations		24,427		1,614		6,634		1,877		31,061		3,491
Corporate debt securities		109,995		3,256		100,977		14,553		210,972		17,809
Total	$	769,045	$	39,023	$	562,156	$	110,492	$	1,331,201	$	149,515