Note 3 - Debt Securities (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

Marketable Securities [Table Text Block]

	Securities Available-For-Sale
	In Thousands
			Gross Unrealized		Gross Unrealized		Fair
	Amortized Cost		Gains		Losses		Value
U.S. Treasury and other U.S. government agencies	$	7,353		—		856		6,497
U.S. Government-sponsored enterprises (GSEs)		177,261		—		32,049		145,212
Mortgage-backed securities		518,727		1		74,290		444,438
Asset-backed securities		47,538		—		2,288		45,250
Corporate bonds		2,500		—		97		2,403
Obligations of states and political subdivisions		218,936		—		39,924		179,012
	$	972,315		1		149,504		822,812

	Securities Available-For-Sale
	In Thousands
			Gross Unrealized		Gross Unrealized		Fair
	Amortized Cost		Gains		Losses		Value
U.S. Treasury and other U.S. government agencies	$	7,320		—		99		7,221
U.S. Government-sponsored enterprises (GSEs)		163,700		20		4,490		159,230
Mortgage-backed securities		465,588		2,726		6,537		461,777
Asset-backed securities		46,583		213		83		46,713
Corporate bonds		2,500		75		—		2,575
Obligations of states and political subdivisions		220,444		2,611		2,986		220,069
	$	906,135		5,645		14,195		897,585

Investments Classified by Contractual Maturity Date [Table Text Block]

	In Thousands
Securities Available-For-Sale	Amortized Cost		Fair Value
Due in one year or less	$	5,078		4,930
Due after one year through five years		79,925		71,315
Due after five years through ten years		270,747		226,085
Due after ten years		616,565		520,482
	$	972,315		822,812

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

	In Thousands
	2022			2021			2020
Gross proceeds	$	42,728			39,652			54,870
Gross realized gains	$	—			137			901
Gross realized losses		(1,620	)		(109	)		(19	)
Net realized gains (losses)	$	(1,620	)		28			882

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
2022	Fair Value		Losses		Included		Fair Value		Losses		Included		Fair Value		Losses
Available-for-Sale Securities:
Debt securities:
U.S. Treasury and other U.S. government agencies	$	—	$	—		—	$	6,497	$	856		3	$	6,497	$	856
U.S. Government-sponsored enterprises (GSEs)		9,747		872		4		135,465		31,177		54		145,212		32,049
Mortgage-backed securities		148,441		14,601		113		295,431		59,689		136		443,872		74,290
Asset-backed securities		35,276		1,607		21		9,974		681		11		45,250		2,288
Corporate bonds		2,403		97		1		—		—		—		2,403		97
Obligations of states and political subdivisions		58,567		6,056		76		120,445		33,868		128		179,012		39,924
	$	254,434	$	23,233		215	$	567,812	$	126,271		332	$	822,246	$	149,504

	In Thousands, Except Number of Securities
	Less than 12 Months						12 Months or More						Total
					Number of						Number of
			Unrealized		Securities				Unrealized		Securities				Unrealized
2021	Fair Value		Losses		Included		Fair Value		Losses		Included		Fair Value		Losses
Available-for-Sale Securities:
Debt securities:
U.S. Treasury and other U.S. government agencies	$	7,221	$	99		3	$	—	$	—		—	$	7,221	$	99
U.S. Government-sponsored enterprises (GSEs)		110,981		2,466		33		45,725		2,024		19		156,706		4,490
Mortgage-backed securities		317,211		4,644		96		54,692		1,893		33		371,903		6,537
Asset-backed securities		17,945		67		9		484		16		1		18,429		83
Corporate bonds		—		—		—		—		—		—		—		—
Obligations of states and political subdivisions		83,510		1,460		74		36,225		1,526		32		119,735		2,986
	$	536,868	$	8,736		215	$	137,126	$	5,459		85	$	673,994	$	14,195