Note M - Leases (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Operating Lease, Expense	$ 1,182,000	$ 1,114,000	$ 1,050,000
Operating Lease, Payments	$ 1,181,000	916,000
Operating Lease, Weighted Average Remaining Lease Term (Year)	6 years 10 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent	5.60%
Operating Lease, Lease Income, Lease Payments	$ 1,967,000	1,788,000
Operating Lease, Right-of-Use Asset	3,363,000	$ 3,521,000		$ 3,832,000
Operating Lease, Liability, Total	$ 3,363,000			$ 3,832,000