Note 7 - Investment Securities (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

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

	March 31, 2021
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	40,709	$	11	$	—	$	40,720
U.S. government agency entities		95,637		705		291		96,051
Mortgage-backed securities		658,371		15,292		5,239		668,424
Collateralized mortgage obligations		10,201		—		74		10,127
Corporate debt securities		93,545		526		549		93,522
Total	$	898,463	$	16,534	$	6,153	$	908,844

	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]

	March 31, 2021
	Securities Available-For-Sale
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	85,713	$	85,764
Due after one year through five years		35,967		35,481
Due after five years through ten years		175,943		180,203
Due after ten years		600,840		607,396
Total	$	898,463	$	908,844

Schedule of Unrealized Loss on Investments [Table Text Block]

	March 31, 2021
	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. government agency entities	$	12,930	$	11	$	23,662	$	280	$	36,592	$	291
Mortgage-backed securities		190,914		4,638		7,903		601		198,817		5,239
Collateralized mortgage obligations		9,946		65		181		9		10,127		74
Corporate debt securities		39,451		549		—		—		39,451		549
Total	$	253,241	$	5,263	$	31,746	$	890	$	284,987	$	6,153

	December 31, 2020
	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	$	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