Note 11 - Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

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

	20 16			2015			2014
Expected option life in years (1)		6.0			6.0			6.0
Expected stock price volatility percentage (2)		25	%		25	%		27	%
Risk-free interest rate percentage (3)		1.4	%		1.8	%		1.9	%
Expected dividend yield (4)		0.50	%		0.44	%		0.46	%
Fair value as of the date of grant	$	5.28		$	5.96		$	6.25

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

	Shares			Weighted Average Exercise Price
Outstanding at December 31, 2015		850,184		$	16.67
Granted		43,000			20.44
Exercised		(307,984	)		14.35
Forfeited		(31,450	)		17.68
Outstanding at December 31, 2016		553,750		$	18.24
Exercisable at December 31, 2016		287,100		$	16.03

Schedule of Nonvested Share Activity [Table Text Block]

	Shares			Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Life (in Years)
Nonvested at December 31, 2015		337,550		$	5.77		5.4
Granted		43,000			5.28		6.6
Vested		(94,650	)		5.64		4.0
Forfeited		(19,250	)		5.38		3.9
Nonvested at December 31, 2016		266,650		$	5.76		5.0

Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]

	Shares				Weighted Average Grant Date Fair Value
Nonvested at December 31, 2015		141,445			$	18.76
Granted		48,600				18.73
Vested		(13,656	)	(1)		18.11
Forfeited		(24,578	)			14.83
Nonvested at December 31, 2016		151,811			$	19.44