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. 29, 2016	Oct. 31, 2015	Oct. 29, 2016	Oct. 31, 2015
Recognized in AOCI:
Gain (loss) before income taxes	$ 253	$ (2,094)	$ (197)	$ (7,064)
Less income tax provision (benefit)	94	(777)	(73)	(2,621)
Net	159	(1,317)	(124)	(4,443)
Reclassified from AOCI to cost of sales:
Loss before income taxes	(1,083)	(2,446)	(2,193)	(3,837)
Less income tax benefit	(402)	(907)	(814)	(1,423)
Net	(681)	(1,539)	(1,379)	(2,414)
Net change to AOCI	$ 840	$ 222	$ 1,255	$ (2,029)