Note 4 - Investment Securities (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

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

	As of 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

	As of December 31, 2021
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	—	$	—	$	—	$	—
U.S. government agency entities		86,475		1,169		135		87,509
Mortgage-backed securities		886,614		9,465		7,414		888,665
Collateralized mortgage obligations		9,547		—		430		9,117
Corporate debt securities		144,231		441		2,654		142,018
Total	$	1,126,867	$	11,075	$	10,633	$	1,127,309

Investments Classified by Contractual Maturity Date [Table Text Block]

	Securities Available-for-Sale
	As of December 31, 2022
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	311,603	$	310,050
Due after one year through five years		213,395		196,616
Due after five years through ten years		168,767		159,448
Due after ten years		928,408		807,234
Total	$	1,622,173	$	1,473,348

Schedule of Unrealized Loss on Investments [Table Text Block]

	As of December 31, 2022
	Less than 12 months				12 months or longer				Total
	Fair		Gross Unrealized		Fair		Gross Unrealized		Fair		Gross 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

	As of December 31, 2021
	Less than 12 months				12 months or longer				Total
	Fair		Gross Unrealized		Fair		Gross Unrealized		Fair		Gross Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	—	$	—	$	—	$	—	$	—	$	—
U.S. government agency entities		—		—		2,337		135		2,337		135
Mortgage-backed securities		527,276		6,659		6,496		755		533,772		7,414
Collateralized mortgage obligations		8,989		417		128		13		9,117		430
Corporate debt securities		103,720		2,122		19,468		532		123,188		2,654
Total	$	639,985	$	9,198	$	28,429	$	1,435	$	668,414	$	10,633