Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 857.8	$ 854.5	$ 771.4
Net other comprehensive (loss) income	(43.1)	7.2	48.6
Ending Balance	892.7	857.8	854.5
Foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(66.1)	(58.8)
Other comprehensive (loss) income before reclassifications and tax	(26.6)	(7.3)
Tax benefit (expense)	0.0	0.0
Other comprehensive (loss) income before reclassifications, net of tax	(26.6)	(7.3)
Reclassifications, before tax	0.0	0.0
Tax benefit (expense)	0.0	0.0
Reclassifications, net of tax	0.0	0.0
Net other comprehensive (loss) income	(26.6)	(7.3)
Ending Balance	(92.7)	(66.1)	(58.8)
Pension benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(82.9)	(95.1)
Other comprehensive (loss) income before reclassifications and tax	(16.3)	11.4
Tax benefit (expense)	4.1	(3.0)
Other comprehensive (loss) income before reclassifications, net of tax	(12.2)	8.4
Reclassifications, before tax	(4.8)	5.5
Tax benefit (expense)	0.9	(1.7)
Reclassifications, net of tax	(3.9)	3.8
Net other comprehensive (loss) income	(16.1)	12.2
Ending Balance	(99.0)	(82.9)	(95.1)
Derivative financial instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(0.8)
Other comprehensive (loss) income before reclassifications and tax	(0.6)
Tax benefit (expense)	0.1
Other comprehensive (loss) income before reclassifications, net of tax	(0.5)
Reclassifications, before tax	0.1
Tax benefit (expense)	0.0
Reclassifications, net of tax	0.1
Net other comprehensive (loss) income	(0.4)
Ending Balance	(1.2)	(0.8)
Derivative financial instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(0.8)	(3.1)
Other comprehensive (loss) income before reclassifications and tax		3.2
Tax benefit (expense)		(1.1)
Other comprehensive (loss) income before reclassifications, net of tax		2.1
Reclassifications, before tax		0.2
Tax benefit (expense)		0.0
Reclassifications, net of tax		0.2
Net other comprehensive (loss) income		2.3
Ending Balance		(0.8)	(3.1)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(149.8)	(157.0)	(205.6)
Other comprehensive (loss) income before reclassifications and tax	(43.5)	7.3
Tax benefit (expense)	4.2	(4.1)
Other comprehensive (loss) income before reclassifications, net of tax	(39.3)	3.2
Reclassifications, before tax	(4.7)	5.7
Tax benefit (expense)	0.9	(1.7)
Reclassifications, net of tax	(3.8)	4.0
Net other comprehensive (loss) income	(43.1)	7.2
Ending Balance	$ (192.9)	$ (149.8)	$ (157.0)