Note 5 - Share-based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Notes Tables

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

	2016						2015
	Class A			Class B			Class A			Class B
Expected dividend yield at date of grant	2.96	to	3.02%	6.67	to	8.12%	2.14	to	2.57%	5.29	to	5.72%
Expected stock price volatility	31.33	to	34.61%	27.64	to	31.77%	30.86	to	34.87%	29.96	to	33.94%
Risk-free interest rate	1.36	to	2.12%	1.36	to	2.12%	1.55	to	1.78%	1.55	to	1.78%
Expected life of options (in years)	6	to	8	6	to	8	5	to	7	5	to	7

Schedule of 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)
Class A
Outstanding at December 31, 2015		1,485,738		$	11.65
Granted		315,620		$	14.64
Exercised		(52,383	)	$	6.59			$	459
Forfeited		(31,146	)	$	12.47
Outstanding at September 30, 2016		1,717,829		$	12.33		6.14	$	6,913
Exercisable at September 30, 2016		1,214,793		$	11.54		5.09	$	5,860
Class B
Outstanding at December 31, 2015		240,673		$	26.31
Granted		52,603		$	36.16
Exercised		(35,534	)	$	16.88			$	632
Forfeited		(5,191	)	$	24.08
Outstanding at September 30, 2016		252,551		$	29.73		6.59	$	1,722
Exercisable at September 30, 2016		169,659		$	27.67		5.56	$	1,539

Schedule of Nonvested Share Activity [Table Text Block]

	Class A Shares Outstanding			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, 2015		183,814		$	12.78		30,635		$	36.93
Granted		20,578		$	15.23		3,430		$	34.00
Vested		(20,892	)	$	5.38		(3,482	)	$	32.31
Forfeited		--			--		--			--
Outstanding at September 30, 2016		183,500		$	13.89		30,583		$	37.13