Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 771.4	$ 778.7	$ 1,002.4
Net other comprehensive income (loss)	48.6	(43.6)	(116.2)
Ending Balance	854.5	771.4	778.7
Foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(89.3)	(70.8)
Other comprehensive income (loss) before reclassifications and tax	30.5	(18.5)
Tax (expense) benefit	0.0	0.0
Other comprehensive income (loss) before reclassifications, net of tax	30.5	(18.5)
Reclassifications, before tax	0.0	0.0
Tax (expense) benefit	0.0	0.0
Reclassifications, net of tax	0.0	0.0
Net other comprehensive income (loss)	30.5	(18.5)
Ending Balance	(58.8)	(89.3)	(70.8)
Pension benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(115.8)	(90.6)
Other comprehensive income (loss) before reclassifications and tax	24.8	(55.4)
Tax (expense) benefit	(8.7)	19.4
Other comprehensive income (loss) before reclassifications, net of tax	16.1	(36.0)
Reclassifications, before tax	7.1	15.8
Tax (expense) benefit	(2.5)	(5.0)
Reclassifications, net of tax	4.6	10.8
Net other comprehensive income (loss)	20.7	(25.2)
Ending Balance	(95.1)	(115.8)	(90.6)
Derivative financial instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(0.5)	(0.6)
Other comprehensive income (loss) before reclassifications and tax	(2.4)	(0.4)
Tax (expense) benefit	0.8	0.1
Other comprehensive income (loss) before reclassifications, net of tax	(1.6)	(0.3)
Reclassifications, before tax	(1.4)	0.6
Tax (expense) benefit	0.4	(0.2)
Reclassifications, net of tax	(1.0)	0.4
Net other comprehensive income (loss)	(2.6)	0.1
Ending Balance	(3.1)	(0.5)	(0.6)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(205.6)	(162.0)	(45.8)
Other comprehensive income (loss) before reclassifications and tax	52.9	(74.3)
Tax (expense) benefit	(7.9)	19.5
Other comprehensive income (loss) before reclassifications, net of tax	45.0	(54.8)
Reclassifications, before tax	5.7	16.4
Tax (expense) benefit	(2.1)	(5.2)
Reclassifications, net of tax	3.6	11.2
Net other comprehensive income (loss)	48.6	(43.6)
Ending Balance	$ (157.0)	$ (205.6)	$ (162.0)