Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Treasury Stock	Retained Earnings	Non-Controlling Interest
Beginning Balance (in shares) at May. 03, 2014		39,262,168
Beginning Balance at May. 03, 2014	$ 392.2	$ 19.6	$ 89.8	$ 24.7	$ (11.4)	$ 269.2	$ 0.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Earned portion of restricted stock awards (in shares)		39,675
Stock award and stock option amortization expense	4.3		4.4		(0.1)
Exercise of options (in shares)		400,193
Exercise of options	4.0	$ 0.3	3.7
Tax benefit from stock option exercises	4.3		4.3
Foreign currency translation adjustments	(33.0)			(33.0)
Net income for year	101.0					101.1	(0.1)
Cash dividends on common stock	(13.8)					(13.8)
Ending Balance (in shares) at May. 02, 2015		39,702,036
Ending Balance at May. 02, 2015	459.0	$ 19.9	102.2	(8.3)	(11.5)	356.5	0.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Earned portion of restricted stock awards (in shares)		430,245
Earned portion of restricted stock awards	0.1	$ 0.1
Stock award and stock option amortization expense	7.4		7.4
Exercise of options (in shares)		47,002
Exercise of options	$ (7.1)	$ 0.1	0.5			(7.7)
Purchase of common stock (in shares)	(1,997,298)	(1,997,298)
Purchase of common stock	$ (62.3)	$ (1.0)				(61.3)
Tax benefit from stock option exercises	2.2		2.2
Foreign currency translation adjustments	(0.3)			(0.1)			(0.2)
Net income for year	84.6					84.6
Cash dividends on common stock	(13.5)					(13.5)
Ending Balance (in shares) at Apr. 30, 2016		38,181,985
Ending Balance at Apr. 30, 2016	470.1	$ 19.1	112.3	(8.4)	(11.5)	358.6	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Earned portion of restricted stock awards (in shares)		146,192
Earned portion of restricted stock awards	(1.1)	$ 0.1
Stock award and stock option amortization expense	12.4		12.4			(1.2)
Exercise of options (in shares)		147,829
Exercise of options	$ 2.7	$ 0.1	2.6			0.0
Purchase of common stock (in shares)	(280,168)	(342,081)
Purchase of common stock	$ (9.8)	$ (0.2)				(9.6)
Tax benefit from stock option exercises	4.9		4.9
Foreign currency translation adjustments	(17.3)			(17.3)			0.0
Net income for year	92.9					92.9
Cash dividends on common stock	(13.7)					(13.7)
Ending Balance (in shares) at Apr. 29, 2017		38,133,925
Ending Balance at Apr. 29, 2017	$ 541.1	$ 19.1	$ 132.2	$ (25.7)	$ (11.5)	$ 427.0	$ 0.0