Net Earnings (Loss) Per Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Oct. 31, 2020	Aug. 01, 2020	Oct. 26, 2019	Jul. 27, 2019	Oct. 31, 2020	Oct. 26, 2019	Dec. 14, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock Repurchase Program, Authorized Amount							$ 50,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 26,669				$ 26,669
Shares Paid for Tax Withholding for Share Based Compensation					410,560
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,932,628		1,218,994		2,849,291	1,529,877
Net Income (Loss) Attributable to Parent	$ 7,515	$ (46,652)	$ 35,931	$ (32,155)	$ (39,137)	$ 3,776
Weighted Average Number of Shares Outstanding, Basic	48,804,000		47,853,000		48,608,000	47,717,000
Average dilutive restricted stock units	235,000		444,000		0	334,000
Average dilutive performance shares	0		0		0	14,000
Average dilutive restricted shares	18,000		12,000		0	11,000
Average Dilutive Performance Share Units	224,000		449,000		0	336,000
Average dilutive stock options	147,000		0		0	0
Earnings Per Share, Basic	$ 0.15		$ 0.75		$ (0.81)	$ 0.08
Earnings Per Share, Diluted	$ 0.15		$ 0.74		$ (0.81)	$ 0.08
Weighted Average Number of Shares Outstanding, Basic and Diluted					48,608,000	47,717,000
Net Income (Loss) Available to Common Stockholders, Basic	$ 7,509		$ 35,910		$ (39,137)	$ 3,774
Weighted Average Number of Shares Outstanding, Diluted	49,428,000		48,758,000		48,608,000	48,412,000
Undistributed Earnings, Basic	$ 6		$ 21		$ 0	$ 2
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	(6)		(20)		0	(2)
Net Income (Loss) Attributable to Parent, Diluted	7,509		35,911		(39,137)	3,774
Undistributed Earnings (Loss) Available to Common Shareholders, Basic	$ (6)		$ (21)		$ 0	$ (2)