Note 6 - Stock Option Plans (Tables)

9 Months Ended

Sep. 30, 2019

Notes Tables

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	September 30, 2019			September 30, 2018
Weighted average risk-free interest rate		1.93	%		1.47-2.63	%
Expected dividend yield		0.59	%		0.41-0.50	%
Expected stock volatility		9.90	%		10.07 - 11.90	%
Expected life in years		6.5			2.5 - 6.5
Per share fair value of options issued during period	$	2.74		$	1.49 - 3.35

Nonvested Restricted Stock Shares Activity [Table Text Block]

			Wtd-Avg
			Grant-Date
	Number of		Fair Value		Grant-Date Fair
	Shares		per Share		Value
Non-vested restricted stock issued in 2019		3,600	$	18.52	$	67,000
Non-vested restricted stock outstanding at September 30, 2019		3,600

The 2007 Stock Option Plan [Member]

Notes Tables

Share-based Payment Arrangement, Option, Activity [Table Text Block]

						Weighted-
				Weighted-		Average
				Average		Remaining		Aggregate
	Number of			Exercise		Contractual		Intrinsic
	Options			Price		Term (years)		Value
Outstanding at December 31, 2017		22,200		$	10.31
Options exercised		(4,700	)		10.00
Outstanding at September 30, 2018		17,500		$	10.39
Outstanding at December 31, 2018		4,700		$	11.37
Options exercised		(300	)		10.00
Options forfeited		(2,000	)		10.72
Outstanding at September 30, 2019		2,400		$	12.08		0.63	$	19,000
Exercisable at September 30, 2019		2,400		$	12.08		0.63	$	19,000

The 2015 Stock Incentive Compensation Plan [Member]

Notes Tables

Share-based Payment Arrangement, Option, Activity [Table Text Block]

						Weighted-
				Weighted-		Average
				Average		Remaining		Aggregate
	Number of			Exercise		Contractual		Intrinsic
	Options			Price		Term (years)		Value
Outstanding at December 31, 2017		11,540		$	17.03
Options granted		252,917			19.79
Outstanding at September 30, 2018		264,457		$	19.79
Outstanding at December 31, 2018		263,457		$	19.78
Options granted		22,000		$	20.21
Options forfeited		(13,180	)	$	20.09
Outstanding at September 30, 2019		272,277		$	19.80		8.06	$	73,000
Exercisable at September 30, 2019		71,837		$	18.97		6.41	$	73,000