Note 11 - Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2014

Disclosure Text Block Supplement [Abstract]

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

	2014			2013			2012
Expected option life in years(1)		6.0			6.1			6.1
Expected stock price volatility percentage(2)		27	%		33	%		37	%
Risk-free interest rate percentage(3)		1.9	%		1.5	%		1.1	%
Expected dividend yield(4)		0.46	%		0.51	%		0.49	%
Fair value as of the date of grant	$	6.25		$	5.46		$	4.81

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

				Weighted
				Average
	Shares			Exercise Price
Outstanding at December 31, 2013		1,015,759		$	14.07
Granted		76,000			21.99
Exercised		(89,192	)		13.61
Forfeited		(24,700	)		13.85
Outstanding at December 31, 2014		977,867		$	14.74
Exercisable at December 31, 2014		695,317		$	13.63

Schedule of Nonvested Share Activity [Table Text Block]

						Weighted
						Average
				Weighted		Remaining
				Average		Contractual
				Grant Date		Life
	Shares			Fair Value		(in Years)
Service-based options:
Nonvested at December 31, 2013		331,450		$	5.30		5.5
Granted		76,000			6.25		6.4
Vested		(101,100	)		5.36		3.8
Forfeited		(23,800	)		4.57		4.8
Nonvested at December 31, 2014		282,550		$	5.60		5.3

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

				Weighted Average
				Grant Date
	Shares			Fair Value
Nonvested at December 31, 2013		117,532		$	13.81
Granted		47,400			22.34
Vested		(14,415	) (1)		15.10
Nonvested at December 31, 2014		150,517		$	16.37