Fair Value Measurements-Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	Aug. 31, 2015	May. 31, 2015	Nov. 30, 2014	Aug. 31, 2014
Liabilities [Abstract]
Contingent consideration related to acquisition	$ 28.6	$ 27.7
Recurring [Member]
Assets [Abstract]
Cash and cash equivalents	108.4		$ 77.3	$ 93.8
Insurance contracts	102.0		104.5	103.3
Bonds and other long-term investments	7.8		8.5	8.2
Interest rate derivatives	3.5		7.4	7.3
Foreign currency derivatives	5.1		4.9	1.6
Total assets	226.8		202.6	214.2
Liabilities [Abstract]
Foreign currency derivatives	1.2		1.4	0.8
Interest rate derivatives	0.2
Contingent consideration related to acquisition	28.6
Total liabilities	30.0
Recurring [Member] | Level 1 [Member]
Assets [Abstract]
Cash and cash equivalents	108.4		77.3	93.8
Insurance contracts	0.0		0.0	0.0
Bonds and other long-term investments	7.8		8.5	8.2
Interest rate derivatives	0.0		0.0	0.0
Foreign currency derivatives	0.0		0.0	0.0
Total assets	116.2		85.8	102.0
Liabilities [Abstract]
Foreign currency derivatives	0.0		0.0	0.0
Interest rate derivatives	0.0
Total liabilities	0.0
Recurring [Member] | Level 2 [Member]
Assets [Abstract]
Cash and cash equivalents	0.0		0.0	0.0
Insurance contracts	102.0		104.5	103.3
Bonds and other long-term investments	0.0		0.0	0.0
Interest rate derivatives	3.5		7.4	7.3
Foreign currency derivatives	5.1		4.9	1.6
Total assets	110.6		116.8	112.2
Liabilities [Abstract]
Foreign currency derivatives	1.2		1.4	0.8
Interest rate derivatives	0.2
Total liabilities	1.4
Recurring [Member] | Level 3 [Member]
Assets [Abstract]
Cash and cash equivalents	0.0		0.0	0.0
Insurance contracts	0.0		0.0	0.0
Bonds and other long-term investments	0.0		0.0	0.0
Interest rate derivatives	0.0		0.0	0.0
Foreign currency derivatives	0.0		0.0	0.0
Total assets	0.0		0.0	0.0
Liabilities [Abstract]
Foreign currency derivatives	0.0		$ 0.0	$ 0.0
Interest rate derivatives	0.0
Contingent consideration related to acquisition	28.6
Total liabilities	$ 28.6