Note 5 - Share-based Compensation (Tables)

6 Months Ended

Jun. 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		(33,234	)	$	5.12			$	336
Forfeited		--			--
Outstanding at June 30, 2016		1,768,124		$	12.30		6.37	$	3,695
Exercisable at June 30, 2016		1,233,942		$	11.50		5.33	$	3,488
Class B
Outstanding at December 31, 2015		240,673		$	26.31
Granted		52,603		$	36.16
Exercised		(32,343	)	$	16.66			$	588
Forfeited		--			--
Outstanding at June 30, 2016		260,933		$	29.49		6.80	$	1,501
Exercisable at June 30, 2016		172,850		$	27.51		5.79	$	1,335

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 June 30, 2016		183,500		$	13.89		30,583		$	37.13