Note 11 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]

	2020					2019					2018
	Shares			Weighted Average Fair Value		Shares			Weighted Average Fair Value		Shares			Weighted Average Fair Value
Nonvested at beginning of year		262,260		$	34.91		262,967		$	33.97		239,637		$	32.37
Granted		121,518			24.65		84,596			35.29		91,400			31.82
Vested		(85,445	)		37.08		(81,772	)		32.19		(55,792	)		25.14
Forfeited		(35,997	)		33.71		(3,531	)		34.85		(12,278	)		31.62
Nonvested at end of year		262,336		$	29.42		262,260		$	34.91		262,967		$	33.97

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

	2020					2019					2018
	Shares			Weighted Average Exercise Price		Shares			Weighted Average Exercise Price		Shares			Weighted Average Exercise Price
Outstanding at beginning of year		10,700		$	30.25		18,900		$	23.92		30,908		$	18.67
Granted		0		NA			0		NA			0		NA
Exercised		(1,000	)		5.19		(8,200	)		15.69		(12,008	)		10.38
Forfeited or expired		0		NA			0		NA			0		NA
Outstanding at end of year		9,700		$	32.83		10,700		$	30.25		18,900		$	23.92
Options exercisable at year-end		9,700		$	32.83		10,700		$	30.25		18,900		$	23.92

Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block]

			Outstanding						Exercisable
					Weighted Average		Weighted				Weighted
Range of					Remaining		Average				Average
Exercise					Contractual		Exercise				Exercise
Prices			Number		Life (Years)		Price		Number		Price
$22.00	-	$23.00		1,000		0.9	$	22.15		1,000		22.15
$27.00	-	$28.00		2,200		1.9		27.66		2,200		27.66
$36.00	-	$37.00		6,500		2.9		36.22		6,500		36.22
Outstanding at year end				9,700		2.4	$	32.83		9,700		32.83

Schedule of Share-based Compensation Shares Authorized Under Stock Option Plans Information Related to Option Outstanding [Table Text Block]

	2020		2019		2018
Minimum exercise price	$	22.15	$	5.19	$	5.19
Maximum exercise price		36.22		36.22		36.22
Average remaining option term (years)		2.4		3.2		3.4

Schedule of Share Based Compensation Arrangement by Share Based Payment Award Options Information Related to Stock Option Grants and Exercised [Table Text Block]

	2020		2019		2018
Aggregate intrinsic value of stock options exercised	$	17,000	$	157,000	$	317,000
Cash received from stock option exercises		3,000		126,000		141,000
Tax benefit realized from stock option exercises		0		0		0
Weighted average per share fair value of stock options granted		NA		NA	NA