Note 8 - Investment Securities (Tables)

3 Months Ended

Mar. 31, 2023

Notes Tables

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

	March 31, 2023
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	270,165	$	34	$	501	$	269,698
U.S. government agency entities		59,734		324		127		59,931
U.S. government sponsored entities		40,000		14		—		40,014
Mortgage-backed securities .		969,966		401		113,065		857,302
Collateralized mortgage obligations		33,877		—		2,910		30,967
Corporate debt securities		298,698		265		15,625		283,338
Total	$	1,672,440	$	1,038	$	132,228	$	1,541,250

	December 31, 2022
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	241,611	$	—	$	1,111	$	240,500
U.S. government agency entities		63,347		384		121		63,610
U.S. government sponsored entities		30,000		—		—		30,000
Mortgage-backed securities .		993,883		194		126,983		867,094
Collateralized mortgage obligations		34,552		—		3,491		31,061
Corporate debt securities		258,780		112		17,809		241,083
Total	$	1,622,173	$	690	$	149,515	$	1,473,348

Investments Classified by Contractual Maturity Date [Table Text Block]

	March 31, 2023
	Securities Available-For-Sale
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	350,165	$	348,984
Due after one year through five years		256,256		241,910
Due after five years through ten years		169,294		160,169
Due after ten years		896,725		790,187
Total	$	1,672,440	$	1,541,250

Schedule of Unrealized Loss on Investments [Table Text Block]

	March 31, 2023
	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	$	172,306	$	501	$	—	$	—	$	172,306	$	501
U.S. government agency entities		6,617		3		1,676		124		8,293		127
Mortgage-backed securities.		127,422		4,819		709,405		108,246		836,827		113,065
Collateralized mortgage obligations		24,326		1,206		6,641		1,704		30,967		2,910
Corporate debt securities		98,411		1,589		114,663		14,036		213,074		15,625
Total	$	429,082	$	8,118	$	832,385	$	124,110	$	1,261,467	$	132,228

	December 31, 2022
	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	$	240,500	$	1,111	$	—	$	—	$	240,500	$	1,111
U.S. government agency entities		—		—		1,806		121		1,806		121
Mortgage-backed securities .		394,123		33,042		452,739		93,941		846,862		126,983
Collateralized mortgage obligations		24,427		1,614		6,634		1,877		31,061		3,491
Corporate debt securities		109,995		3,256		100,977		14,553		210,972		17,809
Total	$	769,045	$	39,023	$	562,156	$	110,492	$	1,331,201	$	149,515