Business Segment Information (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 28, 2014	Feb. 28, 2013	Feb. 28, 2014	Feb. 28, 2013
Reconciliation of segment gross profit to consolidated income before provision for income taxes
Segment gross profit	$ 78.7	$ 76.2	$ 254.4	$ 253.9
Selling, general and administrative	(45.6)	(41.8)	(144.4)	(145.9)
Earnings from joint ventures	0.6	3.2	2.6	5.8
Loss on extinguishment of debt				(0.3)
Interest expense	(10.7)	(10.2)	(32.2)	(31.6)
Interest income	0.3	0.4	0.9	1.1
Income before provision for income taxes	$ 23.3	$ 27.8	$ 81.3	$ 83.0