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

9 Months Ended

Sep. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

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

Nine months ended September 30,	2015			2014
Risk free interest rate		1.06	%		0.69	%
Dividend yield		3.86			4.28
Volatility		26.74			28.12
Expected life (years)		5.00			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, 2014		88,375		$	23.27
Granted		21,000			29.25
Exercised		(12,150	)		17.81
Forfeited		(12,650	)		31.87
Outstanding at September 30, 2015		84,575		$	24.25		2.50	$	444
Exercisable at September 30, 2015		30,375		$	20.87		0.89	$	262

	Number of options			Weighted average exercise price		Weighted average remaining contractual term (in years)		Aggregate intrinsic value
Outstanding at December 31, 2013		115,800		$	23.51
Granted		20,000			25.16
Exercised		(19,425	)		17.76
Forfeited		(24,625	)		29.35
Outstanding at September 30, 2014		91,750		$	23.52		3.33	$	172
Exercisable at September 30, 2014		87,893		$	23.53		2.10	$	384