Note 5 - Debt Securities (Tables)

12 Months Ended

Dec. 31, 2023

Notes Tables

Marketable Securities [Table Text Block]

	December 31, 2023
			Unrealized
Dollars in thousands	Amortized Cost		Gains		Losses		Fair Value
Debt Securities Available for Sale
Taxable debt securities
U.S. Government and agencies and corporations	$	23,295	$	38	$	508	$	22,825
Residential mortgage-backed securities:
Government-sponsored agencies		133,709		729		4,871		129,567
Nongovernment-sponsored entities		78,350		22		4,503		73,869
State and political subdivisions
General obligations		79,323		3		14,995		64,331
Various tax revenues		10,665		—		2,107		8,558
Other revenues		26,822		—		4,782		22,040
Corporate debt securities		39,618		52		1,763		37,907
Asset-backed securities		44,388		81		264		44,205
Total taxable debt securities		436,170		925		33,793		403,302
Tax-exempt debt securities
State and political subdivisions
General obligations		80,144		581		3,716		77,009
Other revenues		24,882		28		2,459		22,451
Total tax-exempt debt securities		105,026		609		6,175		99,460
Total debt securities available for sale	$	541,196	$	1,534	$	39,968	$	502,762

	December 31, 2022
			Unrealized
Dollars in thousands	Amortized Cost		Gains		Losses		Fair Value
Debt Securities Available for Sale
Taxable debt securities
U.S. Government and agencies and corporations	$	20,446	$	83	$	310	$	20,219
Residential mortgage-backed securities:
Government-sponsored agencies		55,184		80		3,808		51,456
Nongovernment-sponsored entities		65,860		48		4,291		61,617
State and political subdivisions
General obligations		82,410		9		19,924		62,495
Various tax revenues		10,699		—		2,591		8,108
Other revenues		29,044		—		6,580		22,464
Corporate debt securities		33,409		44		1,825		31,628
Asset-backed securities		20,009		—		533		19,476
Total taxable debt securities		317,061		264		39,862		277,463
Tax-exempt debt securities
State and political subdivisions
General obligations		93,910		281		6,719		87,472
Water and sewer revenues		17,560		120		1,154		16,526
Lease revenues		7,411		47		411		7,047
Various tax revenues		7,851		—		1,115		6,736
Other revenues		11,274		9		1,326		9,957
Total tax-exempt debt securities		138,006		457		10,725		127,738
Total debt securities available for sale	$	455,067	$	721	$	50,587	$	405,201

Summary of Volume of State and Political Subdivision Securities Held in Portfolio [Table Text Block]

	December 31, 2023
			Unrealized
Dollars in thousands	Amortized Cost		Gains		Losses		Fair Value
California	$	43,903	$	—	$	8,423	$	35,480
Texas		29,284		220		3,604		25,900
Michigan		18,749		8		1,481		17,276
Oregon		14,719		—		3,006		11,713
Pennsylvania		11,214		19		1,231		10,002

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

Dollars in thousands	Proceeds from						Gross realized
			Calls and		Principal
Years ended December 31,	Sales		Maturities		Payments		Gains		Losses
2023	$	135,701	$	4,492	$	40,702	$	1,254	$	1,520
2022		69,211		1,875		37,860		288		996
2021		64,932		8,070		29,869		1,210		785

Investments Classified by Contractual Maturity Date [Table Text Block]

Dollars in thousands	Amortized Cost		Fair Value
Due in one year or less	$	61,455	$	59,934
Due from one to five years		161,414		156,157
Due from five to ten years		112,930		105,048
Due after ten years		205,397		181,623
Total	$	541,196	$	502,762

Schedule of Unrealized Loss on Investments 1 [Table Text Block]

	2023
			Less than 12 months				12 months or more				Total
Dollars in thousands	# of securities in loss position		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Taxable debt securities
U.S. Government agencies and corporations		39	$	11,809	$	287	$	9,329	$	221	$	21,138	$	508
Residential mortgage-backed securities:
Government-sponsored agencies		133		68,815		1,528		32,902		3,343		101,717		4,871
Nongovernment-sponsored entities		35		27,804		1,493		40,274		3,010		68,078		4,503
State and political subdivisions:
General obligations		54		—		—		63,336		14,995		63,336		14,995
Various tax revenues		7		—		—		8,558		2,107		8,558		2,107
Other revenues		21		1,530		56		18,854		4,726		20,384		4,782
Corporate debt securities		21		6,758		341		18,310		1,422		25,068		1,763
Asset-backed securities		17		23,823		110		9,961		154		33,784		264
Tax-exempt debt securities
State and political subdivisions:
General obligations		39		7,479		69		43,626		3,647		51,105		3,716
Other revenues		19		807		28		19,317		2,431		20,124		2,459
Total		385	$	148,825	$	3,912	$	264,467	$	36,056	$	413,292	$	39,968

	2022
			Less than 12 months				12 months or more				Total
Dollars in thousands	# of securities in loss position		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Taxable debt securities
U.S. Government agencies and corporations		28	$	8,012	$	99	$	9,577	$	211	$	17,589	$	310
Residential mortgage-backed securities:
Government-sponsored agencies		58		21,831		1,104		19,459		2,704		41,290		3,808
Nongovernment-sponsored entities		27		35,727		2,974		10,041		1,317		45,768		4,291
State and political subdivisions:
General obligations		56		11,258		1,476		49,858		18,448		61,116		19,924
Various tax revenues		7		1,352		276		6,756		2,315		8,108		2,591
Other revenues		23		6,361		1,040		16,103		5,540		22,464		6,580
Corporate debt securities		20		8,308		591		13,072		1,234		21,380		1,825
Asset-backed securities		13		11,680		277		7,796		256		19,476		533
Tax-exempt debt securities
State and political subdivisions:
General obligations		52		50,671		1,823		26,062		4,896		76,733		6,719
Water and sewer revenues		13		8,800		403		4,471		751		13,271		1,154
Lease revenues		2		3,330		11		1,985		400		5,315		411
Various tax revenues		4		3,597		439		3,139		676		6,736		1,115
Other revenues		7		2,900		393		4,812		933		7,712		1,326
Total		310	$	173,827	$	10,906	$	173,131	$	39,681	$	346,958	$	50,587

Debt Securities, Held-to-Maturity [Table Text Block]

	December 31, 2023
	Amortized		Unrealized				Estimated
Dollars in thousands	Cost		Gains		Losses		Fair Value
Debt Securities Held to Maturity
Tax-exempt debt securities
State and political subdivisions
General obligations	$	68,966	$	—	$	4,029	$	64,937
Water and sewer revenues		7,816		—		417		7,399
Lease revenues		4,151		—		321		3,830
Sales tax revenues		4,446		—		409		4,037
Various tax revenues		5,425		—		536		4,889
Other revenues		3,423		—		196		3,227
Total Debt Securities Held to Maturity	$	94,227	$	—	$	5,908	$	88,319

	December 31, 2022
	Amortized		Unrealized				Estimated
Dollars in thousands	Cost		Gains		Losses		Fair Value
Debt Securities Held to Maturity
Tax-exempt debt securities
State and political subdivisions
General obligations	$	70,401	$	—	$	6,480	$	63,921
Water and sewer revenues		8,006		—		672		7,334
Lease revenues		4,234		—		534		3,700
Sales tax revenues		4,515		—		689		3,826
Various tax revenues		5,511		—		871		4,640
Other revenues		3,496		—		290		3,206
Total Debt Securities Held to Maturity	$	96,163	$	—	$	9,536	$	86,627

Summary of Volume of State and Political Subdivision Securities Held to Maturity [Table Text Block]

	December 31, 2023
	Amortized		Unrealized				Estimated
Dollars in thousands	Cost		Gains		Losses		Fair Value
Texas	$	14,795	$	—	$	854	$	13,941
California		9,450		—		454		8,996
Pennsylvania		8,322		—		439		7,883
Florida		7,331		—		637		6,694
Michigan		6,772		—		503		6,269

Debt Securities Held to Maturity by Credit Rating [Table Text Block]

	December 31, 2023
Dollars in thousands	AAA		AA		A		BBB		Below Investment Grade
Tax-exempt state and political subdivisions	$	14,866	$	72,086	$	7,275	$	—	$	—

	December 31, 2022
Dollars in thousands	AAA		AA		A		BBB		Below Investment Grade
Tax-exempt state and political subdivisions	$	12,846	$	75,932	$	7,385	$	—	$	—

Held to Maturity Investments Classified by Contractual Maturity Date [Table Text Block]

Dollars in thousands	Amortized Cost		Estimated Fair Value
Due in one year or less	$	—	$	—
Due from one to five years		—		—
Due from five to ten years		4,025		3,856
Due after ten years		90,202		84,463
Total	$	94,227	$	88,319