Note 7 - Investment Securities (Tables)

6 Months Ended

Jun. 30, 2021

Notes Tables

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

	June 30, 2021
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	40,458	$	9	$	—	$	40,467
U.S. government agency entities		92,120		1,329		137		93,312
Mortgage-backed securities		739,672		13,640		3,836		749,476
Collateralized mortgage obligations		10,010		—		274		9,736
Corporate debt securities		109,464		659		599		109,524
Total	$	991,724	$	15,637	$	4,846	$	1,002,515

	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]

	June 30, 2021
	Securities Available-For-Sale
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	65,472	$	65,511
Due after one year through five years		71,862		71,254
Due after five years through ten years		161,771		166,473
Due after ten years		692,619		699,277
Total	$	991,724	$	1,002,515

Schedule of Unrealized Loss on Investments [Table Text Block]

	June 30, 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	$	—	$	—	$	2,475	$	137	$	2,475	$	137
Mortgage-backed securities		298,310		3,159		7,583		677		305,893		3,836
Collateralized mortgage obligations		9,574		264		162		10		9,736		274
Corporate debt securities		50,611		352		9,753		247		60,364		599
Total	$	358,495	$	3,775	$	19,973	$	1,071	$	378,468	$	4,846

	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