Note 3 - Investment Securities (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

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

	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

	As of December 31, 2020
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	80,948	$	6	$	6	$	80,948
U.S. government agency entities		99,944		441		546		99,839
Mortgage-backed securities		709,709		17,965		606		727,068
Collateralized mortgage obligations		10,358		—		34		10,324
Corporate debt securities		118,271		367		267		118,371
Total	$	1,019,230	$	18,779	$	1,459	$	1,036,550

Investments Classified by Contractual Maturity Date [Table Text Block]

	Securities Available-for-Sale
	As of December 31, 2021
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	5,005	$	5,009
Due after one year through five years		126,871		124,148
Due after five years through ten years		137,989		141,331
Due after ten years		857,002		856,821
Total	$	1,126,867	$	1,127,309

Schedule of Unrealized Loss on Investments [Table Text Block]

	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

	As of December 31, 2020
	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	$	40,952	$	6	$	—	$	—	$	40,952	$	6
U.S. government agency entities		26,390		102		40,009		444		66,399		546
Mortgage-backed securities		1,694		23		8,093		583		9,787		606
Collateralized mortgage obligations		10,131		25		193		9		10,324		34
Corporate debt securities		58,405		267		—		—		58,405		267
Total	$	137,572	$	423	$	48,295	$	1,036	$	185,867	$	1,459