Note 11 - Stock-based Compensation - Non-full Value Awards (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Outstanding Options, beginning balance (in shares)		109,130
Outstanding Options, beginning balance (in dollars per share)		$ 16.14
Granted Options (in shares)		0	0	0
Granted Options (in dollars per share)		$ 0
Exercised Options (in shares)		(103,530)
Exercised Options (in dollars per share)		$ 16.49
Forfeited Options (in shares)		0
Forfeited Options (in dollars per share)		$ 0
Outstanding Options, ending balance (in shares)		5,600	109,130
Outstanding Options, ending balance (in dollars per share)		$ 9.61	$ 16.14
Outstanding Options at December 31, 2016 (Year)		2 years
Outstanding Options at December 31, 2016	[1]	$ 111
Exercisable Options at December 31, 2016 (in shares)		5,600
Exercisable Options at December 31, 2016 (in dollars per share)		$ 9.61
Exercisable Options at December 31, 2016 (Year)		2 years
Exercisable Options at December 31, 2016	[1]	$ 111

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