CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($) $ in Thousands	Oct. 31, 2025	Apr. 30, 2025
Statement of Financial Position [Abstract]
Supplemental type certificates, accumulated amortization	$ 12,772	$ 12,145
Other assets, accumulated amortization	$ 12,761	$ 12,461
Preferred stock, par value (in dollars per share)	$ 5	$ 5
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, designated classes (in shares)	200,000	200,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares, issued (in shares)	79,978,702	79,772,345
Common stock, shares, outstanding (in shares)	64,279,002	67,180,527
Treasury stock, shares (in shares)	15,699,700	12,591,818