Note 3 - Stock-based Compensation and Shareholders' Equity (Tables)

6 Months Ended

Jun. 30, 2016

Notes Tables

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

Six months ended June 30,	2016			2015
Risk free interest rate		1.14	%		1.06	%
Dividend yield		3.78			3.86
Volatility		22.62			26.74
Expected life (years)		4.20			5.00

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

	Number of options			Weighted average exercise price		Weighted average remaining contractual term (in years)		Aggregate intrinsic value
Outstanding at December 31, 2015		82,875		$	24.33
Granted		23,500			30.40
Exercised		(17,980	)		20.66
Forfeited		(9,725	)		25.61
Outstanding at June 30, 2016		78,670		$	26.82		2.99	$	407
Exercisable at June 30, 2016		23,545		$	22.38		1.12	$	226

	Number of options			Weighted average exercise price		Weighted average remaining contractual term (in years)		Aggregate intrinsic value
Outstanding at December 31, 2014		88,375		$	23.27
Granted		21,000			29.25
Exercised		(11,650	)		17.73
Forfeited		(12,650	)		31.87
Outstanding at June 30, 2015		85,075		$	24.22		2.74	$	440
Exercisable at June 30, 2015		30,875		$	20.85		1.12	$	264