Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	$ 917.0	$ 854.4	$ 892.7	$ 857.8
Other comprehensive (loss) income before reclassifications and tax	2.4	23.8	10.6	0.6
Tax benefit (expense)	0.5		0.7	(0.3)
Other comprehensive income (loss) before reclassifications, net of tax	2.9	23.8	11.3	0.3
Reclassifications, before tax	1.7	0.6	4.3	2.3
Tax benefit (expense)	(0.4)	(0.2)	(1.0)	(0.5)
Reclassifications, net of tax	1.3	0.4	3.3	1.8
Other comprehensive (loss) income, net of tax	4.2	24.2	14.6	2.1
Ending Balance	940.4	872.6	940.4	872.6
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(182.5)	(171.9)	(192.9)	(149.8)
Other comprehensive (loss) income, net of tax	4.2	24.2	14.6	2.1
Ending Balance	(178.3)	(147.7)	(178.3)	(147.7)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(84.6)	(90.3)	(92.7)	(66.1)
Other comprehensive (loss) income before reclassifications and tax	2.4	23.7	10.5	(0.5)
Tax benefit (expense)	0.0		0.0	0.0
Other comprehensive income (loss) before reclassifications, net of tax	2.4	23.7	10.5	(0.5)
Reclassifications, before tax	0.0	0.0	0.0	0.0
Tax benefit (expense)	0.0	0.0	0.0	0.0
Reclassifications, net of tax	0.0	0.0	0.0	0.0
Other comprehensive (loss) income, net of tax	2.4	23.7	10.5	(0.5)
Ending Balance	(82.2)	(66.6)	(82.2)	(66.6)
Pension Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(98.2)	(81.3)	(99.0)	(82.9)
Other comprehensive (loss) income before reclassifications and tax	0.0	0.0	0.0	0.0
Tax benefit (expense)	0.0		0.0	0.0
Other comprehensive income (loss) before reclassifications, net of tax	0.0	0.0	0.0	0.0
Reclassifications, before tax	1.6	0.7	2.3	2.7
Tax benefit (expense)	(0.4)	(0.2)	(0.3)	(0.6)
Reclassifications, net of tax	1.2	0.5	2.0	2.1
Other comprehensive (loss) income, net of tax	1.2	0.5	2.0	2.1
Ending Balance	(97.0)	(80.8)	(97.0)	(80.8)
Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	0.3	(0.3)	(1.2)	(0.8)
Other comprehensive (loss) income before reclassifications and tax	0.0	0.1	0.1	1.1
Tax benefit (expense)	0.5		0.7	(0.3)
Other comprehensive income (loss) before reclassifications, net of tax	0.5	0.1	0.8	0.8
Reclassifications, before tax	0.1	(0.1)	2.0	(0.4)
Tax benefit (expense)	0.0	0.0	(0.7)	0.1
Reclassifications, net of tax	0.1	(0.1)	1.3	(0.3)
Other comprehensive (loss) income, net of tax	0.6	0.0	2.1	0.5
Ending Balance	$ 0.9	$ (0.3)	$ 0.9	$ (0.3)