Note 9 - Shareholders' Equity (Details Textual) - USD ($) Pure in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020	Dec. 31, 2021
Stock Repurchased and Retired During Period, Shares	951,010	910,700
Payments for Repurchase of Common Stock	$ 4,002,000	$ 3,882,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 2,194,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross	46,400	19,600
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number	292,766	410,615		427,580
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate	0.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 109,000	$ 12,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period	140,916	21,665
Proceeds from Stock Options Exercised	$ 464,000
Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period	227,000	21,772
Share-Based Payment Arrangement, Expense	$ 145,000	$ 104,000
Share-Based Payment Arrangement, Option [Member]
Share-Based Payment Arrangement, Expense	25,000	$ 43,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 147,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years 6 months
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	46,400
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	46,400	19,600	5,009,750
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period	3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period	5 years
Incentive Plan 2020 [Member]
Common Stock, Capital Shares Reserved for Future Issuance	1,800,000
Incentive Plan 2020 [Member] | Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period	227,000	21,772
Share-Based Payment Arrangement, Expense	$ 145,000	$ 104,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 878,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years 7 months 9 days