Note 13 - Stock Based Compensation (Details) - Stock Options Oustanding by Range of Exercise Prices (USD $)	6 Months Ended
	Jun. 30, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 23.78
Range of Exercise Prices - Upper limit	$ 23.78
Number of shares outstanding (in Shares)	41,800
Options outstanding weighted average remaining contractual life (Years)	1 year 36 days
Options outstanding weighted average exercise price	$ 23.78
Number of shares exercisable (in Shares)	41,800
Options exercisable weighted average exercise price	$ 23.78
$24.50 - $24.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 24.50
Range of Exercise Prices - Upper limit	$ 24.50
Number of shares outstanding (in Shares)	30,800
Options outstanding weighted average remaining contractual life (Years)	1 year 328 days
Options outstanding weighted average exercise price	$ 24.50
Number of shares exercisable (in Shares)	30,800
Options exercisable weighted average exercise price	$ 24.50
$26.19 - $27.67 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 26.19
Range of Exercise Prices - Upper limit	$ 27.67
Number of shares outstanding (in Shares)	48,100
Options outstanding weighted average remaining contractual life (Years)	2 years 292 days
Options outstanding weighted average exercise price	$ 26.20
Number of shares exercisable (in Shares)	48,100
Options exercisable weighted average exercise price	$ 26.20
$28.42 - $28.42 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 28.42
Range of Exercise Prices - Upper limit	$ 28.42
Number of shares outstanding (in Shares)	46,100
Options outstanding weighted average remaining contractual life (Years)	3 years 255 days
Options outstanding weighted average exercise price	$ 28.42
Number of shares exercisable (in Shares)	46,100
Options exercisable weighted average exercise price	$ 28.42
$30.31 - $30.31 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Lower limit	$ 30.31
Range of Exercise Prices - Upper limit	$ 30.31
Number of shares outstanding (in Shares)	44,328
Options outstanding weighted average remaining contractual life (Years)	4 years 255 days
Options outstanding weighted average exercise price	$ 30.31
Number of shares exercisable (in Shares)	44,328
Options exercisable weighted average exercise price	$ 30.31