Note F - Long-term Debt (Details Textual) - USD ($) $ in Thousands					3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 21, 2021	Jun. 10, 2021	Apr. 14, 2020	Apr. 17, 2017	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Letters of Credit Outstanding, Amount					$ 1,000		$ 1,000		$ 1,000
Proceeds from Lines of Credit, Total							0
Interest Expense, Debt, Total					100	$ 200	200	$ 300
Gain (Loss) on Extinguishment of Debt, Total					$ (0)	$ 10,000	$ (0)	$ 10,000
Revolving Credit Facility [Member] | Bloomberg Short-Term Bank Yield Index Rate [Member] | Texas Capital Bank [Member]
Debt Instrument, Basis Spread on Variable Rate	2.25%
Debt Instrument, Interest Rate, Effective Percentage					3.74%		3.74%
New Credit Facility [Member]
Long-Term Line of Credit, Total					$ 10,000		$ 10,000		10,000
Line of Credit Facility, Remaining Borrowing Capacity					14,000		14,000
New Credit Facility [Member] | Revolving Credit Facility [Member] | Texas Capital Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 25,000
Debt Instrument, Term (Year)	3 years
Texas Capital Credit Facility [Member]
Long-Term Line of Credit, Total									5,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage				0.50%
Line of Credit Facility, Collateral Fees, Percentage				0.50%
Interest Expense, Debt, Total									400
Repayments of Long-term Lines of Credit									$ 12,100
Texas Capital Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate				1.95%
Texas Capital Credit Facility [Member] | Prime Rate [Member]
Debt Instrument, Basis Spread on Variable Rate				0.75%
Texas Capital Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity				$ 20,000
Texas Capital Credit Facility [Member] | Standby Letters of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity				$ 5,000
Paycheck Protection Program CARES Act [Member]
Proceeds from Notes Payable, Total			$ 10,000
Notes Payable, Total					$ 10,000		$ 10,000
Gain (Loss) on Extinguishment of Debt, Total		$ 10,000