Note 7 - Investment Securities (Tables)

9 Months Ended

Sep. 30, 2020

Notes Tables

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

	September 30, 2020
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	99,968	$	12	$	—	$	99,980
U.S. government agency entities		104,661		465		530		104,596
Mortgage-backed securities		709,756		20,045		557		729,244
Collateralized mortgage obligations		222		—		11		211
Corporate debt securities		146,368		288		147		146,509
Total	$	1,060,975	$	20,810	$	1,245	$	1,080,540

	December 31, 2019
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	74,926	$	10	$	—	$	74,936
U.S. government agency entities		90,452		663		319		90,796
U.S. government sponsored entities		225,000		—		557		224,443
Mortgage-backed securities		880,040		8,574		824		887,790
Collateralized mortgage obligations		569		—		17		552
Corporate debt securities		172,743		605		23		173,325
Total	$	1,443,730	$	9,852	$	1,740	$	1,451,842

Investments Classified by Contractual Maturity Date [Table Text Block]

	September 30, 2020
	Securities Available-For-Sale
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	182,047	$	182,289
Due after one year through five years		44,028		44,044
Due after five years through ten years		176,079		178,429
Due after ten years		658,821		675,778
Total	$	1,060,975	$	1,080,540

Schedule of Unrealized Loss on Investments [Table Text Block]

	September 30, 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. government agency entities	$	21,824	$	94	$	40,793	$	436	$	62,617	$	530
Mortgage-backed securities		1,924		20		8,944		537		10,868		557
Collateralized mortgage obligations		—		—		211		11		211		11
Corporate debt securities		45,762		147		—		—		45,762		147
Total	$	69,510	$	261	$	49,948	$	984	$	119,458	$	1,245

	December 31, 2019
	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	$	48,829	$	172	$	3,570	$	147	$	52,399	$	319
U.S. government sponsored entities		—		—		224,443		557		224,443		557
Mortgage-backed securities		43,719		36		120,801		788		164,520		824
Collateralized mortgage obligations		—		—		552		17		552		17
Corporate debt securities		51,791		23		—		—		51,791		23
Total	$	144,339	$	231	$	349,366	$	1,509	$	493,705	$	1,740