Revenue - Cumulative Effect of Adoption (Details) - USD ($) $ in Millions	Oct. 31, 2018	Jul. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventory, Net	$ 360.5	$ 334.1
Prepaid Expense and Other Assets, Current	67.6	52.3
Other current liabilities	183.0	224.6
Deferred income taxes	12.9	4.2
Retained earnings	$ 1,192.6	1,122.1
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventory, Net		326.8
Prepaid Expense and Other Assets, Current		66.3
Other current liabilities		86.9
Deferred income taxes		5.3
Retained earnings		1,127.4
Accounting Standards Update 2014-09 | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventory, Net		334.1
Prepaid Expense and Other Assets, Current		52.3
Other current liabilities		86.6
Deferred income taxes		4.2
Retained earnings		1,122.1
Accounting Standards Update 2014-09 | Adjustments for ASC 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventory, Net		(7.3)
Prepaid Expense and Other Assets, Current		14.0
Other current liabilities		0.3
Deferred income taxes		1.1
Retained earnings		$ 5.3