Note 9 - Share-based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

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

	2022			2021			2020
Expected dividend yield at date of grant		3.39	%		2.15	%		1.84	%
Expected stock price volatility		35.52	%		34.85	%		33.62	%
Risk-free interest rate		2.33	%		0.91	%		1.35	%
Expected life of options (in years)		6.3			7.01			7.39

Share-Based Payment Arrangement, Activity [Table Text Block]

	Number of Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Terms (Years)		Aggregate Intrinsic Value (In thousands)
Common Stock
Outstanding at December 31, 2021		477,640	$	30.88
Granted		127,227	$	36.67
Exercised		23,581	$	13.17
Outstanding at December 31, 2022		581,286	$	32.86		5.44	$	4,739
Exercisable at December 31, 2022		323,140	$	26.97		3.55	$	4,369

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value, Intrinsic Value of Exercised and Vested in Period, and Fair Value of Vested in Period [Table Text Block]

	2022		2021		2020
Weighted average grant date fair value of stock options granted	$	9.43	$	12.55	$	18.67
Intrinsic value of stock options exercised (in thousands)	$	648	$	3,535	$	25,912
Intrinsic value of stock options vested (in thousands)	$	4,369	$	4,805	$	1,965

Schedule of Nonvested Share Activity [Table Text Block]

	Common Stock Outstanding		Common Stock Weighted Average Grant Date Fair Value Per Share
Outstanding at December 31, 2021		12,698	$	42.92
Granted		—	$	—
Vested		—	$	—
Forfeited		—	$	—
Outstanding at December 31, 2022		12,698	$	42.92