Note 9 - Stock-based Compensation Plans and Warrants - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018	Dec. 31, 2017
Outstanding (in shares)	492,500		507,500
Outstanding, weighted average exercise price (in dollars per share)	$ 11.66		$ 11.66
Outstanding, average remaining contractual term (Year)	109 days		1 year 109 days	2 years 109 days
Outstanding, aggregate intrinsic value	$ 3,834		$ 3,834	$ 3,934
Granted (in shares)	0		0
Granted, weighted average exercise price (in dollars per share)
Forfeited, Expired or canceled (in shares)			15,000
Forfeited, Expired or canceled, weighted average exercise price (in dollars per share)			$ 11.75
Forfeited, Expired or canceled, aggregate intrinsic value			$ 100
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	0
Exercised, weighted average exercise price (in dollars per share)
Outstanding (in shares)	492,500	[1]	492,500	507,500
Outstanding, weighted average exercise price (in dollars per share)	$ 11.66		$ 11.66	$ 11.66
Options exercisable at December 31, 2019 (in shares)	492,500
Options exercisable, weighted average exercise price (in dollars per share)	$ 11.66
Options exercisable, average remaining contractual term (Year)	109 days
Options exercisable, aggregate intrinsic value	$ 3,834
Weighted-average years of remaining contractual life of options outstanding at December 31, 2019 (Year)	109 days

[1] Exercise prices vary from $9.88 to $12.51, and expiration dates vary from January 2020 to December 2021.