Note 6 - Share-based Compensation (Tables)

6 Months Ended

Jun. 30, 2021

Notes Tables

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

	2021			2020
Expected dividend yield at date of grant		2.15	%		1.84	%
Expected stock price volatility		34.85	%		33.62	%
Risk-free interest rate		0.91	%		1.35	%
Expected life of options (in years)		7.0			7.4

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, 2020		600,571		$	25.31		5.58	$	11,665
Granted		101,091		$	44.96
Exercised		(68,284	)	$	13.34			$	2,122
Expired		(22,837	)	$	9.74
Forfeited		(53,763	)	$	40.48
Outstanding at June 30, 2021		556,778		$	29.52		6.17	$	9,942
Exercisable at June 30, 2021		290,668		$	21.57		4.80	$	7,314

Schedule of Nonvested Share Activity [Table Text Block]

	Common Shares Outstanding			Weighted Average Grant Date Fair Value Per Share
Outstanding at December 31, 2020		6,005		$	38.30
Granted		12,698			42.92
Vested		--			--
Forfeited		(6,005	)	$	38.30
Outstanding at June 30, 2021		12,698		$	42.92