Note 6 - Share-based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Notes Tables

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

	2018		2017
	Common Stock (formerly Class A)		Class A		Class B
Expected dividend yield at date of grant	2.59	%	2.62	%	8.06	%
Expected stock price volatility	32.47	%	32.45	%	26.75	%
Risk-free interest rate	2.51	%	2.18	%	2.18	%
Expected life of options (in years)	7.3		6.8		6.8

Share-based Compensation, Activity [Table Text Block]

	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Terms (Years)		Aggregate Intrinsic Value (In thousands)
Common Stock (formerly Class A)
Outstanding at December 31, 2017		1,746,634		$	13.88
Granted		116,276		$	36.12
Exercised		(380,958	)	$	13.82			$	8,048
Forfeited		(21,383	)	$	26.18
Outstanding at September 30, 2018		1,460,569		$	15.49		4.92	$	33,756
Exercisable at September 30, 2018		1,068,429		$	13.26		3.84	$	27,077
Class B
Outstanding at December 31, 2017		276,716		$	31.78
Granted		--		$	--
Exercised/Settled in Recapitalization		(276,716	)	$	31.78			$	5,937
Forfeited		--		$	--
Outstanding at September 30, 2018		--		$	--		--	$	--
Exercisable at September 30, 2018		--		$	--		--	$	--

Schedule of Nonvested Share Activity [Table Text Block]

	Common (formerly Class A) Shares Outstanding			Common (formerly Class A) Weighted Average Grant Date Fair Value Per Share		Class B Shares Outstanding			Class B Weighted Average Grant Date Fair Value Per Share
Outstanding at December 31, 2017		81,667		$	13.80		13,611		$	36.65
Granted		6,793			36.80		--			--
Vested/Settled in Recapitalization		--			--		(13,611	)		36.65
Forfeited		(10,289	)	$	15.23		--		$	--
Outstanding at September 30, 2018		78,171		$	15.61		--		$	--