Note 5 - Derivative Financial Instruments - Derivatives Instruments, Statements of Financial Performance and Financial Position (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Oct. 31, 2021	Oct. 30, 2021	Oct. 31, 2020	Oct. 30, 2021	Oct. 31, 2020
Gain before income taxes	$ 221		$ 2,131	$ 974	$ 7,211
Less income tax provision	53		510	233	1,725
Net	168		1,621	741	5,486
Gain (loss) before income taxes	1,483		(12)	4,540	(1,844)
Less income tax provision (benefit)	355		(3)	1,086	(441)
Net	1,128		(9)	3,454	(1,403)
Net change to AOCI	$ (960)	$ (960)	$ 1,630	$ (2,713)	$ 6,889