Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2016	Oct. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	$ 771.4
Ending Balance	784.7
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(89.3)	$ (70.8)
Other comprehensive (loss) income before reclassifications and tax	(12.4)	(10.6)
Tax benefit (expense)	0.0	0.0
Other comprehensive (loss) income before reclassifications, net of tax	(12.4)	(10.6)
Reclassifications, before tax	0.0	0.0
Tax benefit (expense)	0.0	0.0
Reclassifications, net of tax	0.0	0.0
Other comprehensive (loss) income, net of tax	(12.4)	(10.6)
Ending Balance	(101.7)	(81.4)
Pension benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(115.8)	(90.6)
Other comprehensive (loss) income before reclassifications and tax	0.0	(9.1)
Tax benefit (expense)	0.0	3.4
Other comprehensive (loss) income before reclassifications, net of tax	0.0	(5.7)
Reclassifications, before tax	3.4	6.9
Tax benefit (expense)	(1.0)	(2.2)
Reclassifications, net of tax	2.4	4.7
Other comprehensive (loss) income, net of tax	2.4	(1.0)
Ending Balance	(113.4)	(91.6)
Derivative financial instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(0.5)	(0.6)
Other comprehensive (loss) income before reclassifications and tax	1.6	(1.2)
Tax benefit (expense)	(0.5)	0.4
Other comprehensive (loss) income before reclassifications, net of tax	1.1	(0.8)
Reclassifications, before tax	(0.1)	0.3
Tax benefit (expense)	0.0	(0.1)
Reclassifications, net of tax	(0.1)	0.2
Other comprehensive (loss) income, net of tax	1.0	(0.6)
Ending Balance	0.5	(1.2)
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(205.6)	(162.0)
Other comprehensive (loss) income before reclassifications and tax	(10.8)	(20.9)
Tax benefit (expense)	(0.5)	3.8
Other comprehensive (loss) income before reclassifications, net of tax	(11.3)	(17.1)
Reclassifications, before tax	3.3	7.2
Tax benefit (expense)	(1.0)	(2.3)
Reclassifications, net of tax	2.3	4.9
Other comprehensive (loss) income, net of tax	(9.0)	(12.2)
Ending Balance	$ (214.6)	$ (174.2)