Stock Option Plans (Tables)

12 Months Ended

Dec. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Option Activity

	2020			2019
Options outstanding at the beginning of the year		1,363,694			1,434,280
Options granted		280,750			120,000
Options forfeited		(9,125	)		(26,500	)
Options exercised		(147,394	)		(164,086	)
Options outstanding at the end of the year		1,487,925			1,363,694
Options exercisable at the end of the year		985,475			932,094
Common stock available for future grants at the end of the year		104,372			44,875
Weighted average exercise price per share:
Granted	$	23.05		$	19.88
Forfeited		21.72			23.29
Exercised		14.51			10.54
Outstanding		20.26			19.08
Exercisable		18.99			17.50

Summary of Options Outstanding

Options Outstanding						Options Exercisable
Range of Exercise Prices	Number Outstanding		Weighted- Average Remaining Contractual Life (Years)	Weighted- Average Exercise Price		Number Exercisable		Weighted- Average Exercise Price
$9.26 to $16.08		290,200	2	$	12.39		290,200	$	12.39
$16.09 to $21.35		282,000	6		18.41		204,500		17.95
$21.36 to $22.86		350,375	7		22.14		261,375		21.97
$22.87 to $23.97		255,450	9		23.17		11,350		23.94
$23.98 to $28.20		309,900	7		24.80		218,050		24.94
		1,487,925					985,475

Assumptions Used to Value Option Grants

	2020	2019
Expected life in years	6	5 - 6
Interest rate	.30 - 1.63%	1.52 - 2.39%
Volatility	.358 - .384	.358 - .375
Dividend yield	2.0 - 2.2%	2.0 - 2.2%