Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Jul. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax
Beginning Balance	$ 992.9	$ 892.7
Other comprehensive (loss) income before reclassifications and tax	(0.7)	8.2
Tax benefit (expense)	(1.0)	0.2
Other comprehensive income (loss) before reclassifications, net of tax	(1.7)	8.4
Reclassifications, before tax	3.6	2.6
Tax benefit (expense)	(0.7)	(0.6)
Reclassifications, net of tax	2.9	2.0
Reclassifications, net of tax	1.2	10.4
Ending Balance	1,052.6	917.0
Curtailment charge	0.8	0.0
Accumulated other comprehensive loss	(182.8)		$ (184.0)
Reclassification, Other
Accumulated Other Comprehensive Income (Loss), Net of Tax
Accumulated other comprehensive loss	4.0
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax
Beginning Balance	(184.0)	(192.9)
Reclassifications, net of tax	1.2	10.4
Ending Balance	(182.8)	(182.5)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax
Beginning Balance	(74.0)	(92.7)
Other comprehensive (loss) income before reclassifications and tax	(5.0)	8.1
Tax benefit (expense)	0.0	0.0
Other comprehensive income (loss) before reclassifications, net of tax	(5.0)	8.1
Reclassifications, before tax	0.0	0.0
Tax benefit (expense)	0.0	0.0
Reclassifications, net of tax	0.0	0.0
Reclassifications, net of tax	(5.0)	8.1
Ending Balance	(79.0)	(84.6)
Pension Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax
Beginning Balance	(110.0)	(99.0)
Other comprehensive (loss) income before reclassifications and tax	4.0	0.0
Tax benefit (expense)	(1.0)	0.0
Other comprehensive income (loss) before reclassifications, net of tax	3.0	0.0
Reclassifications, before tax	3.6	0.7
Tax benefit (expense)	(0.5)	0.1
Reclassifications, net of tax	3.1	0.8
Reclassifications, net of tax	6.1	0.8
Ending Balance	(103.9)	(98.2)
Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax
Beginning Balance	0.0	(1.2)
Other comprehensive (loss) income before reclassifications and tax	0.3	0.1
Tax benefit (expense)	0.0	0.2
Other comprehensive income (loss) before reclassifications, net of tax	0.3	0.3
Reclassifications, before tax	0.0	1.9
Tax benefit (expense)	(0.2)	(0.7)
Reclassifications, net of tax	(0.2)	1.2
Reclassifications, net of tax	0.1	1.5
Ending Balance	$ 0.1	$ 0.3