Note 5 - Derivative Financial Instruments - Derivatives Instruments, Statements of Financial Performance and Financial Position (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 28, 2017	Jan. 30, 2016	Jan. 28, 2017	Jan. 30, 2016
Recognized in AOCI:
Gain (loss) before income taxes	$ 176	$ 620	$ (21)	$ (6,444)
Less income tax provision (benefit)	65	230	(8)	(2,391)
Net	111	390	(13)	(4,053)
Reclassified from AOCI to cost of sales:
Loss before income taxes	(651)	(2,171)	(2,844)	(6,008)
Less income tax benefit	(242)	(806)	(1,056)	(2,229)
Net	(409)	(1,365)	(1,788)	(3,779)
Net change to AOCI	$ 520	$ 1,755	$ 1,775	$ (274)