Note 6 - Recently Issued Accounting Pronouncements (Details Textual) - USD ($)	3 Months Ended
	Jul. 29, 2017	Jul. 29, 2017	Jul. 30, 2016
Income Tax Expense (Benefit)		$ 19,769,000	$ 15,070,000
Accounting Standards Update 2016-09 [Member]
Income Tax Expense (Benefit)	$ (81,000)
Reclassification of Excess Tax Benefits from Financing to Operating Activities [Member] | Three Months Ended July 30, 2016 [Member]
Prior Period Reclassification Adjustment	$ 28,000
Reclassification of Deferred Taxes from Current to Non-current [Member] | April 29, 2017 [Member]
Prior Period Reclassification Adjustment		$ 3,900,000