Note 10 - Stock Plans (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value [Table Text Block]

	2022					2021					2020
				Weighted-					Weighted-					Weighted-
	Shares			average grant		Shares			average grant		Shares			average grant
	granted			date fair value		granted			date fair value		granted			date fair value
Director plan		18,000	(2)	$	49.85		12,500	(2)	$	52.00		6,000	(2)	$	56.63
Omnibus plan		16,520	(3)		49.85		13,552	(3)		52.00		11,761	(3)		55.06
Omnibus plan		50	(1)		35.91		50	(1)		58.17		50	(1)		57.62
Omnibus plan		-					36	(3)		58.17		500	(2)		34.02
Omnibus plan		-					476	(2)		52.62		-			-
Total		34,570		$	49.83		26,614		$	52.03		18,311		$	55.00

Nonvested Restricted Stock Shares Activity [Table Text Block]

	2012 & 2022 Stock incentive plans
	Director			Omnibus			Total			Weighted- average grant date fair value
Non-vested balance at December 31, 2019		11,200			15,961			27,161		$	49.48
Granted		6,000			12,311			18,311			55.00
Forfeited		-			-			-
Vested		(7,798	)		(7,597	)		(15,395	)		48.47
Non-vested balance at December 31, 2020		9,402			20,675			30,077		$	53.36
Granted		12,500			14,114			26,614			52.03
Forfeited		-			(439	)		(439	)		52.66
Vested		(6,982	)		(6,227	)		(13,209	)		51.23
Non-vested balance at December 31, 2021		14,920			28,123			43,043		$	53.20
Granted		18,000			16,570			34,570			49.83
Forfeited		-			(3,428	)		(3,428	)		52.13
Vested		(9,048	)		(2,651	)		(11,699	)		52.83
Non-vested balance at December 31, 2022		23,872			38,614			62,486		$	51.46

Share-Based Payment Arrangement, Stock Appreciation Right, Activity [Table Text Block]

	Awards			Weighted-average grant date fair value		Weighted-average remaining contractual term (years)
Outstanding December 31, 2019		97,264		$	9.47		7.5
Granted		-			-		-
Exercised		-			-		-
Forfeited		-			-		-
Outstanding December 31, 2020		97,264		$	9.47		6.5
Granted		-
Exercised		(2,932	)		3.48
Forfeited		-
Outstanding December 31, 2021		94,332		$	9.66		5.5
Granted		-
Exercised		(3,608	)		4.20
Forfeited		(3,591	)		14.41
Outstanding December 31, 2022		87,133		$	9.69		4.5

Share-Based Payment Arrangement, Cost by Plan [Table Text Block]

(dollars in thousands)	2022		2021		2020
Stock-based compensation expense:
2012 Director stock incentive plan	$	623	$	422	$	434
2012 Omnibus stock incentive plan		615		640		740
2022 Omnibus stock incentive plan		1		-		-
Employee stock purchase plan		32		44		27
Total stock-based compensation expense	$	1,271	$	1,106	$	1,201

Share-Based Payment Arrangement, Nonvested Award, Cost [Table Text Block]

	As of
(dollars in thousands)	December 31, 2022
Unrecognized stock-based compensation expense:
2012 Director stock incentive plan	$	773
2012 Omnibus stock incentive plan		811
2022 Omnibus stock incentive plan		1
Total unrecognized stock-based compensation expense	$	1,585