Note 11 - Option Activity (Details)	12 Months Ended
	Dec. 31, 2016 $ / shares shares
Balance (in shares) | shares	850,184
Balance (in dollars per share) | $ / shares	$ 16.67
Granted (in shares) | shares	43,000
Granted (in dollars per share) | $ / shares	$ 20.44
Exercised (in shares) | shares	(307,984)
Exercised (in dollars per share) | $ / shares	$ 14.35
Forfeited (in shares) | shares	(31,450)
Forfeited (in dollars per share) | $ / shares	$ 17.68
Balance (in shares) | shares	553,750
Balance (in dollars per share) | $ / shares	$ 18.24
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number | shares	287,100
Exercisable at December 31, 2016 (in dollars per share) | $ / shares	$ 16.03