Note 3 - Debt and Equity Securities (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

Marketable Securities [Table Text Block]

	March 31, 2021
	Securities Available-For-Sale
	In Thousands
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Market Value
U.S. Government-sponsored enterprises (GSEs)	$	127,112	$	109	$	3,196	$	124,025
Mortgage-backed securities		287,126		4,825		3,289		288,662
Asset-backed securities		39,755		397		22		40,130
Corporate bonds		2,500		44		—		2,544
Obligations of states and political subdivisions		159,570		2,302		3,301		158,571
	$	616,063	$	7,677	$	9,808	$	613,932

	December 31, 2020
	Securities Available-For-Sale
	In Thousands
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Market Value
U.S. 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

Investments Classified by Contractual Maturity Date [Table Text Block]

	Available-For-Sale
	In Thousands
	Amortized Cost		Estimated Market Value
Due in one year or less	$	1,196	$	1,196
Due after one year through five years		40,212		40,767
Due after five years through ten years		188,093		184,576
Due after ten years		386,562		387,393
	$	616,063	$	613,932

Schedule of Unrealized Loss on Investments [Table Text Block]

	In Thousands, Except Number of Securities
	Less than 12 Months						12 Months or More						Total
March 31, 2021	Fair Value		Unrealized Losses		Number of Securities Included		Fair Value		Unrealized Losses		Number of Securities Included		Fair Value		Unrealized Losses
Available-for-Sale Securities:
GSEs	$	107,005	$	3,196		42	$	—	$	—		—	$	107,005	$	3,196
Mortgage-backed securities		135,822		3,268		59		6,569		21		12		142,391		3,289
Asset-backed securities		5,409		22		2		—		—		—		5,409		22
Obligations of states and political subdivisions		74,576		3,301		75		—		—		—		74,576		3,301
	$	322,812	$	9,787		178	$	6,569	$	21		12	$	329,381	$	9,808

	In Thousands, Except Number of Securities
	Less than 12 Months						12 Months or More						Total
December 31, 2020	Fair Value		Unrealized Losses		Number of Securities Included		Fair Value		Unrealized Losses		Number of Securities Included		Fair Value		Unrealized Losses
Available-for-Sale 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