Note A - Basis of Presentation and Summary of Significant Accounting Policies - Calculation of Basic and Diluted Net Income Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Numerator
Net income (loss)	$ 1,916	$ (4,015)	$ 7,806	$ (3,443)
Denominator
Basic weighted average common shares outstanding (in shares)	6,200,712	6,564,765	6,296,408	6,733,781
Dilutive effect of stock options and restricted stock (in shares)	126,000		105,000
Diluted weighted average common shares outstanding (in shares)	6,326,777	6,564,765	6,401,021	6,733,781
Basic net income (loss) per common share (in dollars per share)	$ 0.31	$ (0.61)	$ 1.24	$ (0.51)
Diluted net income (loss) per common share (in dollars per share)	$ 0.30	$ (0.61)	$ 1.22	$ (0.51)