Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Preferred Stock [Member] Series C Preferred Stock [Member]	Preferred Stock [Member] Series D Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member] Series C Preferred Stock [Member]	Treasury Stock [Member] Common Treasury Stock [Member]	Total
Beginning and end of year (in shares) at Apr. 30, 2016	150,000		50,589,000				150,000	4,033,000
Beginning and end of year at Apr. 30, 2016	$ 150		$ 506	$ 34,570	$ 190,733	$ (1,807)	$ (5,100)	$ (12,900)	$ 206,152
Beginning of year (in shares) at May. 02, 2015		120,000	50,418,000
Beginning of year at May. 02, 2015		$ 120	$ 504	37,759	129,773	(2,524)
Series D preferred redeemed (in shares)		(120,000)
Series D preferred redeemed		$ (120)		(5,791)
Stock options exercised (in shares)			171,000
Stock options exercised			$ 2	846
Stock-based compensation				228
Stock-based tax benefits				1,528
Net income					61,198				61,198
Common stock cash dividend
Preferred stock dividends & accretion					(238)
Cash flow hedges						783			783
Other						(66)			(66)
Beginning and end of year (in shares) at Apr. 29, 2017	150,000		50,616,000				150,000	4,033,000
Beginning and end of year at Apr. 29, 2017	$ 150		$ 506	35,638	227,928	(604)	$ (5,100)	$ (12,900)	245,618
Beginning of year (in shares) at Apr. 30, 2016	150,000		50,589,000				150,000	4,033,000
Beginning of year at Apr. 30, 2016	$ 150		$ 506	34,570	190,733	(1,807)	$ (5,100)	$ (12,900)	206,152
Series D preferred redeemed (in shares)
Series D preferred redeemed
Stock options exercised (in shares)			27,000
Stock options exercised				365
Stock-based compensation				208
Stock-based tax benefits				495
Net income					107,045				107,045
Common stock cash dividend					(69,850)
Preferred stock dividends & accretion
Cash flow hedges						1,110			1,110
Other						93			93
Beginning and end of year (in shares) at Apr. 28, 2018	150,000		50,651,000				150,000	4,033,000
Beginning and end of year at Apr. 28, 2018	$ 150		$ 507	36,358	307,824	4,601	$ (5,100)	$ (12,900)	331,440
Beginning of year (in shares) at Apr. 29, 2017	150,000		50,616,000				150,000	4,033,000
Beginning of year at Apr. 29, 2017	$ 150		$ 506	35,638	227,928	(604)	$ (5,100)	$ (12,900)	$ 245,618
Series D preferred redeemed (in shares)
Series D preferred redeemed
Stock options exercised (in shares)			35,000						34,650
Stock options exercised			$ 1	559
Stock-based compensation				161
Stock-based tax benefits
Net income					149,774				$ 149,774
Common stock cash dividend					(69,878)
Preferred stock dividends & accretion
Cash flow hedges						5,227			5,227
Other						$ (22)			$ (22)