Note 10 - Shareholders' Equity (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
The2004 Plan Member | Granted in 2004 and 2005 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
The2004 Plan Member
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	5,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	3,350,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Stock Repurchased and Retired During Period, Shares	973,100	1,019,553
Payments for Repurchase of Common Stock	$ 2,110,000	$ 2,206,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 1,278,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	120,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	225,000	580,000		1,070,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		30,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	0.00%		[1]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 340,000	$ 1,057,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 107,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 164 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	475,000	490,000
Proceeds from Stock Options Exercised	$ 765,000	$ 775,000

[1] The fair value calculation was based on the stock options granted during the year.