Net Earnings (Loss) Per Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Oct. 27, 2018	Oct. 28, 2017	Jul. 29, 2017	Oct. 27, 2018	Oct. 28, 2017	Dec. 14, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	$ 24	$ 16		$ (9)	$ (4)
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				349,660
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	472,748	918,177		422,776	505,496
Net Income (Loss) Attributable to Parent	$ 59,697	$ 48,395	$ 13,612	$ 21,075	$ 13,612
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	(24)	(16)		(9)	(4)
Net Income (Loss) Available to Common Stockholders, Basic	59,673	48,379		21,066	13,608
Undistributed Earnings, Basic	24	16		9	4
Net Income (Loss) Attributable to Parent, Diluted	$ 59,673	$ 48,379		$ 21,066	$ 13,608
Weighted Average Number of Shares Outstanding, Basic	47,184,000	46,705,000		47,050,000	46,611,000
Weighted Average Number of Shares Outstanding, Diluted	47,824,000	47,006,000		47,689,000	47,144,000
Earnings Per Share, Basic	$ 1.26	$ 1.04		$ 0.45	$ 0.29
Earnings Per Share, Diluted	$ 1.25	$ 1.03		$ 0.44	$ 0.29
Average dilutive restricted stock units	463,000	162,000		516,000	389,000
Average dilutive performance shares	42,000	113,000		38,000	127,000
Average dilutive restricted shares	11,000	7,000		13,000	8,000
Average Dilutive Performance Share Units	124,000	19,000		72,000	9,000