Note 7 - Investment Securities (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

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

	March 31, 2020
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. government agency entities	$	110,650	$	151	$	391	$	110,410
U.S. government sponsored entities		175,000		45		—		175,045
Mortgage-backed securities		883,097		27,570		663		910,004
Collateralized mortgage obligations		459		—		11		448
Corporate debt securities		161,026		10		1,770		159,266
Total	$	1,330,232	$	27,776	$	2,835	$	1,355,173

	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]

	March 31, 2020
	Securities Available-For-Sale
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	82,224	$	81,977
Due after one year through five years		254,226		252,788
Due after five years through ten years		86,506		87,304
Due after ten years		907,276		933,104
Total	$	1,330,232	$	1,355,173

Schedule of Unrealized Loss on Investments [Table Text Block]

	March 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. government agency entities	$	57,554	$	240	$	3,034	$	151	$	60,588	$	391
Mortgage-backed securities		693		4		11,585		659		12,278		663
Collateralized mortgage obligations		—		—		448		11		448		11
Corporate debt securities		119,505		1,522		19,752		248		139,257		1,770
Total	$	177,752	$	1,766	$	34,819	$	1,069	$	212,571	$	2,835

	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