Condensed Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2022	Sep. 30, 2022
Statement Of Financial Position [Abstract]
Allowance for uncollectable accounts	$ 0	$ 0
Common stock, par value	$ 0.01666	$ 0.01666
Common stock, shares authorized	54,000,500	54,000,500
Common stock, shares issued	35,938,206	35,776,752
Treasury stock, shares	300,272	377,232