Note 3 - Stock-based Compensation and Shareholders' Equity (Tables)

9 Months Ended

Sep. 30, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Assumptions Used in Option Pricing Model

For the Nine Months Ended September 30,	2019			2018
Risk free interest rate		2.52	%		2.15	%
Dividend yield		3.36	%		1.24	%
Volatility		16.44	%		18.12	%
Expected life (years)		4.17			4.20

Stock Option Activity

	Number of options			Weighted average exercise price		Weighted average remaining contractual term (in years)		Aggregate intrinsic value
Outstanding at December 31, 2018		95,075		$	35.11
Granted		24,700			38.15
Exercised		(8,775	)		25.64
Forfeited		(1,500	)		37.20
Outstanding at September 30, 2019		109,500		$	36.53		2.34	$	357
Exercisable at September 30, 2019		36,350		$	29.95		0.72	$	318

	Number of options			Weighted average exercise price		Weighted average remaining contractual term (in years)		Aggregate intrinsic value
Outstanding at December 31, 2017		85,525		$	30.94
Granted		25,000			43.60
Exercised		(10,000	)		24.86
Forfeited		(1,600	)		32.52
Outstanding at September 30, 2018		98,925		$	34.73		2.74	$	1,105
Exercisable at September 30, 2018		26,525		$	27.46		0.90	$	489