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 Apr. 27, 2013		38,455,853
Beginning Balance at Apr. 27, 2013	$ 289.6	$ 19.2	$ 81.5	$ 15.7	$ (11.4)	$ 184.4	$ 0.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Earned portion of restricted stock awards (in shares)		27,000
Stock award and stock option amortization expense	3.3		3.3
Exercise of options (in shares)		779,315
Exercise of options	5.0	$ 0.4	4.6
Tax benefit from stock option exercises	0.4		0.4
Foreign currency translation adjustments	9.0			9.0
Net income for year	96.2					96.1	0.1
Cash dividends on common stock	(11.3)					(11.3)
Ending Balance (in shares) at May. 03, 2014		39,262,168
Ending 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