Note 13 - Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

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

	2020			2019			2018
Expected option life in years(1)		6.0			6.0			6.0
Expected stock price volatility percentage(2)		28	%		28	%		26	%
Risk-free interest rate percentage(3)		0.6	%		2.2	%		2.8	%
Expected dividend yield(4)		0.80	%		0.58	%		0.48	%
Fair value as of the date of grant	$	3.85		$	3.93		$	4.13

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

	Shares			Weighted Average Exercise Price
Outstanding at December 31, 2019		1,263,513		$	9.87
Granted		41,500			15.37
Exercised		(580,933	)		8.25
Forfeited		(12,300	)		12.37
Outstanding at December 31, 2020		711,780		$	11.47
Exercisable at December 31, 2020		379,218		$	9.97

Schedule of Nonvested Share Activity [Table Text Block]

	Shares			Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Life (in Years)
Nonvested at December 31, 2019		477,980		$	3.45		5.1
Granted		41,500			3.85		6.4
Vested		(175,818	)		3.07		3.2
Forfeited		(11,100	)		3.43		4.3
Nonvested at December 31, 2020		332,562		$	3.71		4.8

Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]

	Shares			Weighted Average Grant Date Fair Value
Nonvested at December 31, 2019		207,179		$	11.44
Granted		73,205			16.44
Vested		(109,304	)(1)		11.79
Forfeited		(16,719	)		7.49
Nonvested at December 31, 2020		154,361		$	13.99