Note 7 - Investment Securities (Tables)

6 Months Ended

Jun. 30, 2020

Notes Tables

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

	June 30, 2020
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	99,935	$	1	$	9	$	99,927
U.S. government agency entities		107,558		499		664		107,393
Mortgage-backed securities		779,492		23,428		508		802,412
Collateralized mortgage obligations		314		—		13		301
Corporate debt securities		135,695		385		11		136,069
Total	$	1,122,994	$	24,313	$	1,205	$	1,146,102

	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]

	June 30, 2020
	Securities Available-For-Sale
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	181,868	$	182,062
Due after one year through five years		54,118		54,320
Due after five years through ten years		155,525		157,920
Due after ten years		731,483		751,800
Total	$	1,122,994	$	1,146,102

Schedule of Unrealized Loss on Investments [Table Text Block]

	June 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. treasury securities	$	59,969	$	9	$	—	$	—	$	59,969	$	9
U.S. government agency entities		48,739		419		15,476		245		64,215		664
Mortgage-backed securities		1,440		10		9,921		498		11,361		508
Collateralized mortgage obligations		—		—		301		13		301		13
Corporate debt securities		38,537		11		—		—		38,537		11
Total	$	148,685	$	449	$	25,698	$	756	$	174,383	$	1,205

	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