Income per Share - Schedule of Computation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Jul. 27, 2019	Jul. 28, 2018
Earnings Per Share [Abstract]
Net Income	$ 28.3	$ 23.7
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Denominator for Basic Income per Share-Weighted Average Shares Outstanding and Vested/Unissued Restricted Stock Units (in shares)	37,534,451	37,350,444
Dilutive Potential Common Shares-Employee Stock Options, Restricted Stock Awards and Restricted Stock Units (in shares)	132,603	287,058
Denominator for Diluted Income per Share (in shares)	37,667,054	37,637,502
Basic and Diluted Income per Share:
Basic Income per Share (in dollars per share)	$ 0.75	$ 0.63
Diluted Income per Share (in dollars per share)	$ 0.75	$ 0.63