Note 5 - Share-based Compensation (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

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

	2020			2019
Expected dividend yield at date of grant		1.83	%		2.85	%
Expected stock price volatility		33.79	%		34.05	%
Risk-free interest rate		1.74	%		2.48	%
Expected life of options (in years)		8			8

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)
Outstanding at December 31, 2019		1,245,922		$	18.08		4.45	$	59,631
Granted		48,934		$	65.80
Exercised		(260,481	)	$	12.08			$	12,059
Forfeited		--		$	--
Outstanding at March 31, 2020		1,034,375		$	21.85		5.36	$	25,579
Exercisable at March 31, 2020		613,484		$	15.16		3.88	$	18,600

Schedule of Nonvested Share Activity [Table Text Block]

	Common Shares Outstanding			Weighted Average Grant Date Fair Value Per Share
Outstanding at December 31, 2019		84,176		$	17.23
Granted		--			--
Vested		(34,622	)		13.17
Forfeited		--		$	--
Outstanding at March 31, 2020		49,554		$	20.06