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. 30, 2016	Jan. 31, 2015	Jan. 30, 2016	Jan. 31, 2015
Recognized in AOCI:
Gain (loss) before income taxes	$ 620	$ (1,096)	$ (6,444)	$ 152
Less income tax provision (benefit)	230	(407)	(2,391)	56
Net	390	(689)	(4,053)	96
Reclassified from AOCI to cost of sales:
(Loss) gain before income taxes	(2,171)	249	(6,008)	526
Less income tax (benefit) provision	(806)	92	(2,229)	195
Net	(1,365)	157	(3,779)	331
Net change to AOCI	$ 1,755	$ (846)	$ (274)	$ (235)