Note 12 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

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

	2019					2018					2017
	Shares			Weighted Average Fair Value		Shares			Weighted Average Fair Value		Shares			Weighted Average Fair Value
Nonvested at beginning of year		262,967		$	33.97		239,637		$	32.37		228,343		$	26.09
Granted		84,596			35.29		91,400			31.82		94,592			37.11
Vested		(81,772	)		32.19		(55,792	)		25.14		(74,979	)		20.17
Forfeited		(3,531	)		34.85		(12,278	)		31.62		(8,319	)		23.75
Nonvested at end of year		262,260		$	34.91		262,967		$	33.97		239,637		$	32.37

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

	2019					2018					2017
	Shares			Weighted Average Exercise Price		Shares			Weighted Average Exercise Price		Shares			Weighted Average Exercise Price
Outstanding at beginning of year		13,700		$	30.51		15,808		$	29.62		16,808		$	29.17
Granted		0		NA			0		NA			0		NA
Exercised		(4,000	)		24.91		(2,108	)		23.77		(1,000	)		22.15
Forfeited or expired		0		NA			0		NA			0		NA
Outstanding at end of year		9,700		$	32.83		13,700		$	30.51		15,808		$	29.62
Options exercisable at year-end		9,700		$	32.83		13,700		$	30.51		9,308		$	25.00

	2019					2018					2017
	Shares			Weighted Average Exercise Price		Shares			Weighted Average Exercise Price		Shares			Weighted Average Exercise Price
Outstanding at beginning of year		5,200		$	6.57		15,100		$	7.20		44,275		$	9.86
Granted		0		NA			0		NA			0		NA
Exercised		(4,200	)		6.90		(9,900	)		7.53		(27,675	)		11.50
Forfeited or expired		0		NA			0		NA			(1,500	)		6.33
Outstanding at end of year		1,000		$	5.19		5,200		$	6.57		15,100		$	7.20
Options exercisable at year-end		1,000		$	5.19		5,200		$	6.57		15,100		$	7.20

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	1.9	$	22.15		1,000		22.15
$27.00	-	$28.00		2,200	2.9		27.66		2,200		27.66
$36.00	-	$37.00		6,500	3.9		36.22		6,500		36.22
Outstanding at year end				9,700	3.4	$	32.83		9,700		32.83

			Outstanding					Exercisable
					Weighted Average	Weighted				Weighted
Range of					Remaining	Average				Average
Exercise					Contractual	Exercise				Exercise
Prices			Number		Life (Years)	Price		Number		Price
$ 5.00	-	$ 6.00		1,000	0.9		5.19		1,000		5.19
Outstanding at year end				1,000	0.9	$	5.19		1,000	$	5.19

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

	2019		2018		2017
Minimum exercise price	$	22.15	$	22.15	$	22.15
Maximum exercise price		36.22		36.22		36.22
Average remaining option term (years)		3.4		4.1		5.0

	2019		2018		2017
Minimum exercise price	$	5.19	$	5.19	$	5.19
Maximum exercise price		5.19		8.60		8.60
Average remaining option term (years)		0.9		1.5		1.7

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

	2019		2018		2017
Aggregate intrinsic value of stock options exercised	$	43,000	$	17,000	$	15,000
Cash received from stock option exercises		97,000		33,000		0
Tax benefit realized from stock option exercises		0		0		0
Weighted average per share fair value of stock options granted	NA		NA		NA

	2019		2018		2017
Aggregate intrinsic value of stock options exercised	$	114,000	$	300,000	$	594,000
Cash received from stock option exercises		29,000		108,000		318,000
Tax benefit realized from stock option exercises		0		0		208,000
Weighted average per share fair value of stock options granted	NA		NA		NA