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. 27, 2018	Oct. 28, 2017	Oct. 27, 2017	Oct. 27, 2018	Oct. 28, 2017	Oct. 27, 2017
Gain before income taxes	$ 1,076		$ 5,523	$ 7,424		$ 4,556
Less income tax provision	257		2,049	1,776		1,690
Net	819		3,474	5,648		2,866
Gain before income taxes	4,596		362	13,530		393
Less income tax provision	1,061		135	3,125		146
Net	3,535		227	10,405		247
Net change to AOCI	$ (2,716)	$ 3,247	$ 3,247	$ (4,756)	$ 2,619	$ 2,619

Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount before tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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