Summary of Significant Accounting Policies - Treasury Stock (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	May 29, 2015	May 31, 2016	May 31, 2015	May 31, 2014
Shares repurchased (in shares)	4,185,960
Share repurchase price (in dollars per share)	$ 31.90
Cash tender offer amount	$ 133.5
Fees and expenses	$ 1.2
Shares repurchased		$ 16.8
Change in treasury stock due to restricted stock grants		(0.3)	$ 4.2	$ (0.2)
Change in treasury stock due to restricted stock awards and exercise of stock options, net of shares withheld to satisfy statutory tax obligations		3.6
Change in treasury stock due to exercise of stock options, net of shares withheld to satisfy statutory tax obligations		6.7	6.3	7.8
Repurchase of treasury shares		18.8	151.5	1.0
Treasury Stock
Total increase (decrease) in treasury stock		21.3		(1.8)
Change in treasury stock due to restricted stock grants		(4.8)	(0.7)	(2.2)
Change in treasury stock due to restricted stock awards and exercise of stock options, net of shares withheld to satisfy statutory tax obligations				2.8
Change in treasury stock due to exercise of stock options, net of shares withheld to satisfy statutory tax obligations		2.3	4.2	5.0
Repurchase of treasury shares		$ 18.8	$ 151.5	$ 1.0