Note 10 - Stock Option Transactions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Balance, options outstanding (in shares)	822,500		842,500	862,500
Balance, weighted-average exercise price (in dollars per share)	$ 11.82		$ 11.84	$ 11.92
Expired or canceled, amount (in shares)	(315,000)		(20,000)	(20,000)
Expired or canceled, weighted-average exercise price (in dollars per share)	$ 12.09		$ 12.60	$ 15.25
Balance, options outstanding (in shares)	507,500	[1]	822,500	842,500
Balance, weighted-average exercise price (in dollars per share)	$ 11.66		$ 11.82	$ 11.84
Options exercisable at December 31, 2015 (in shares)	507,500
Options exercisable at December 31, 2015 (in dollars per share)	$ 11.66
Weighted-average years of remaining contractual life of options outstanding at December 31, 2015	4 years 109 days

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