Note 5 - Capital Stock and Transactions With Related Parties (Details Textual) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended			72 Months Ended
	Jan. 29, 2019	Aug. 04, 2017	Jan. 27, 2017	Apr. 27, 2019	Apr. 28, 2018	Apr. 29, 2017	Apr. 28, 2018	Apr. 29, 2016
Payments of Ordinary Dividends, Common Stock	$ 135,200	$ 69,900	$ 69,900	$ 135,247	$ 69,878	$ 69,850
Common Stock, Dividends, Per Share, Cash Paid	$ 2.90	$ 1.50	$ 1.50
Stock Repurchase Program, Number of Shares Authorized to be Repurchased								1,600,000
Stock Repurchased During Period, Shares							502,060
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased					1,097,940		1,097,940
Treasury Stock, Shares, Acquired				0	0	0
CMA [Member]
Related Party Transaction, Amounts of Transaction				$ 10,200	$ 9,800	$ 8,300
Accounts Payable, Total				$ 2,400	$ 2,400		$ 2,400