Note 12 - Share-based Compensation - Stock Option Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Outstanding, options (in shares)	676,846
Outstanding, weighted average exercise price (in dollars per share)	$ 15.70
Outstanding, weighted average remaining life (Year)	2 years 346 days	2 years 361 days
Outstanding, aggregate intrinsic value	$ 714	$ 2,230
Granted (in shares)	184,994
Granted, weighted average exercise price (in dollars per share)	$ 17.22
Exercised (in shares)	(75,444)
Exercised, weighted average exercise price (in dollars per share)	$ 6.71
Lapsed or cancelled (in shares)	(85,265)
Lapsed or cancelled, weighted average exercise price (in dollars per share)	$ 17.77
Outstanding, options (in shares)	701,131	676,846
Outstanding, weighted average exercise price (in dollars per share)	$ 16.82	$ 15.70
Exercisable, options (in shares)	496,153
Exercisable, weighted average exercise price, options (in dollars per share)	$ 16.54
Exercisable, weighted average remaining life, options (Year)	2 years 120 days
Exercisable, aggregate intrinsic value, options	$ 714