Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	May 31, 2018	Aug. 31, 2018	Aug. 31, 2017	Nov. 30, 2017
Income Tax Examination [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%		35.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability				$ 381.4
U.S. Tax Act, Incomplete Accounting, Transition Tax				72.3
U.S. Tax Act, Incomplete Accounting, Repatriation and Withholding Tax Impact				73.2
U.S. Tax Act, Non-cash Income Tax Expense (Benefit)	$ (10.3)		$ 297.9	308.2
U.S. Tax Act, Incomplete Accounting, Withholding Tax on Repatriation Earnings				5.2
U.S. Tax Act, Incomplete Accounting, Changes in Transition Tax				4.3
Effective income tax rate reconciliation, tax credit, amount	20.6	$ 6.6		326.0	$ 17.3
Unrecognized tax benefits, reduction resulting from lapse of applicable statute of limitations	2.0			5.5	6.8
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	1.4	1.2		1.4	1.2
Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions	1.0			1.5
Domestic Tax Authority
Income Tax Examination [Line Items]
Shares issued, tax benefit	$ 7.9	0.8		12.4	9.4
Foreign Tax Authority
Income Tax Examination [Line Items]
Unrecognized tax benefits, reduction resulting from lapse of applicable statute of limitations		$ 4.6
Effective income tax rate reconciliation, change in deferred tax assets valuation allowance, amount				$ 0.5	$ 0.1