Stock-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Jul. 30, 2016	Apr. 29, 2017	Apr. 30, 2016	Apr. 25, 2015
Stock-Based Compensation
Expense recognized		$ 10,551	$ 9,647	$ 11,377
Cash received for exercises of stock options		3,566	420	1,397
Stock Options
Stock-Based Compensation
Cash received for exercises of stock options		$ 3,600	$ 400	1,400
Number of Shares
Outstanding, at beginning of period (in shares)	1,411,000	1,411,000
Granted (in shares)	497,198	497,000
Canceled (in shares)		(97,000)
Exercised (in shares)		(302,000)
Outstanding, at end of period (in shares)		1,509,000	1,411,000
Exercisable (in shares)		591,000
Weighted Average Exercise Price
Outstanding, at beginning of period (in dollars per share)	$ 19.39	$ 19.39
Granted (in dollars per share)		25.99
Canceled (in dollars per share)		25.28
Exercised (in dollars per share)		11.82
Outstanding, at end of period (in dollars per share)		22.70	$ 19.39
Exercisable (in dollars per share)		$ 18.27
Additional information
Weighted Average Remaining Contractual Term, Outstanding		7 years 7 months 6 days	7 years 4 months 24 days
Weighted Average Remaining Contractual Term, Exercisable		6 years 2 months 12 days
Aggregate Intrinsic Value, Outstanding		$ 7,638	$ 9,489
Aggregate Intrinsic Value, Exercised		4,871	$ 600	$ 2,000
Aggregate Intrinsic Value, Exercisable		5,688
Unrecognized compensation cost		$ 2,300
Period for recognition of unrecognized compensation costs		1 year 4 months 24 days
Vested during the period (in shares)		300,000
Fair value assumptions
Risk-free interest rate (as a percent)		1.30%	1.54%	1.59%
Dividend rate (as a percent)		1.54%	1.20%	1.00%
Expected life in years		5 years	5 years	5 years
Stock price volatility (as a percent)		38.87%	44.37%	54.40%
Fair value per share (in dollars per share)		$ 7.99	$ 9.69	$ 10.45
Stock Options | Minimum
Stock-Based Compensation
Purchase price of common stock at date of grant (as a percent)		100.00%
Vesting period		1 year
Stock Options | Maximum
Stock-Based Compensation
Vesting period		4 years
Stock Options | Selling, General and Administrative Expense
Stock-Based Compensation
Expense recognized		$ 3,400	$ 3,200	$ 3,000
Stock Options | Former Long-Term Equity Award Plan
Stock-Based Compensation
Award expiration term		10 years