Note 6 - Leases (Details Textual) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Oct. 26, 2019	Oct. 26, 2019	Apr. 28, 2019	Apr. 27, 2019
Operating Lease, Liability, Total	$ 49,545	$ 49,545
Operating Lease, Right-of-Use Asset	$ 49,576	$ 49,576		$ 0
Operating Lease, Weighted Average Remaining Lease Term	3 years 9 months 18 days	3 years 9 months 18 days
Operating Lease, Weighted Average Discount Rate, Percent	3.38%	3.38%
Operating Lease, Expense	$ 3,400	$ 6,700
Short-term Lease, Cost	$ 3,000	8,000
Operating Lease, Payments		$ 7,500
Accounting Standards Update 2016-02 [Member]
Operating Lease, Liability, Total			$ 55,500
Operating Lease, Right-of-Use Asset			$ 55,500