Note 3 - Debt and Equity Securities (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Marketable Securities [Table Text Block]

	Securities Available-For-Sale
	In Thousands
			Gross Unrealized		Gross Unrealized		Estimated Market
	Amortized Cost		Gains		Losses		Value
Government-sponsored enterprises (GSEs)	$	125,712		328		135		125,905
Mortgage-backed securities		258,774		5,636		620		263,790
Asset-backed securities		36,394		582		19		36,957
Corporate bonds		2,500		100		—		2,600
Obligations of states and political subdivisions		147,462		4,229		400		151,291
	$	570,842		10,875		1,174		580,543

	Securities Available-For-Sale
	In Thousands
			Gross Unrealized		Gross Unrealized		Estimated Market
	Amortized Cost		Gains		Losses		Value
Government-sponsored enterprises (GSEs)	$	59,735		48		204		59,579
Mortgage-backed securities		265,648		2,300		635		267,313
Asset-backed securities		27,531		1		303		27,229
Corporate bonds		—		—		—		—
Obligations of states and political subdivisions		67,293		559		828		67,024
	$	420,207		2,908		1,970		421,145

Investments Classified by Contractual Maturity Date [Table Text Block]

	In Thousands
Securities Available-For-Sale	Amortized Cost		Estimated Market Value
Due in one year or less	$	1,196		1,198
Due after one year through five years		26,325		26,542
Due after five years through ten years		107,341		108,184
Due after ten years		140,812		143,872
		275,674		279,796
Mortgage and asset-backed securities		295,168		300,747
	$	570,842		580,543

Schedule of Realized Gain (Loss) [Table Text Block]

	In Thousands
	2020			2019			2018
Gross proceeds	$	54,870			37,325			39,857
Gross realized gains	$	901			75			102
Gross realized losses		(19	)		(343	)		(752	)
Net realized gains (losses)	$	882			(268	)		(650	)

Schedule of Unrealized Loss on Investments [Table Text Block]

	In Thousands, Except Number of Securities
	Less than 12 Months						12 Months or More						Total
					Number of						Number of
			Unrealized		Securities				Unrealized		Securities				Unrealized
2020	Fair Value		Losses		Included		Fair Value		Losses		Included		Fair Value		Losses
Available-for-Sale Securities:
Debt securities:
GSEs	$	47,991	$	135		18	$	—	$	—		—	$	47,991	$	135
Mortgage-backed securities		78,381		573		29		6,776		47		12		85,157		620
Asset-backed securities		4,950		19		3		—		—		—		4,950		19
Corporate bonds		—		—		—		—		—		—		—		—
Obligations of states and political subdivisions		44,061		394		33		689		6		1		44,750		400
	$	175,383	$	1,121		83	$	7,465	$	53		13	$	182,848	$	1,174

	In Thousands, Except Number of Securities
	Less than 12 Months						12 Months or More						Total
					Number of						Number of
			Unrealized		Securities				Unrealized		Securities				Unrealized
2019	Fair Value		Losses		Included		Fair Value		Losses		Included		Fair Value		Losses
Available-for-Sale Securities:
Debt securities:
GSEs	$	16,507	$	114		5	$	24,658	$	90		9	$	41,165	$	204
Mortgage-backed securities		45,862		182		21		56,917		453		52		102,779		635
Asset-backed securities		17,807		161		10		7,317		142		4		25,124		303
Corporate bonds		—		—		—		—		—		—		—		—
Obligations of states and political subdivisions		30,423		783		26		3,858		45		10		34,281		828
	$	110,599	$	1,240		62	$	92,750	$	730		75	$	203,349	$	1,970