Note 9 - Stock-based Compensation (Details) - Non-full Value Awards, All of Which Have Been Granted As Stock Options - Jun. 30, 2015 - USD ($) $ / shares in Units, $ in Thousands		Total
Non-full Value Awards, All of Which Have Been Granted As Stock Options [Abstract]
Outstanding at December 31, 2014		154,915
Outstanding at December 31, 2014		$ 15.19
Outstanding at June 30, 2015		145,190
Outstanding at June 30, 2015		$ 15.09
Outstanding at June 30, 2015		3 years 36 days
Outstanding at June 30, 2015	[1]	$ 860
Exercised		(9,725)
Exercised		$ 16.65

[1] The intrinsic value of a stock option is the difference between the fair value of the underlying stock and the exercise price of the option.