Note G - 401(k) Plan (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employer Contribution Common Stock [Member]
Defined Contribution Plan, Percentage of Specified Salary Amount Matched by Employer	50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%
Defined Contribution Plan, Cost	$ 1,324,000	$ 1,249,000	$ 1,197,000
Employer Contribution Cash [Member]
Defined Contribution Plan, Percentage of Specified Salary Amount Matched by Employer	50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%
Defined Contribution Plan, Cost	$ 859,000	813,000	802,000
Certain Employees [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	3.00%
The 401 (k) for Employees at Amron Division of the AMTEC Subsidiary [Member]
Defined Contribution Plan, Cost	$ 465,000	$ 443,000	$ 387,000