Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Feb. 28, 2018	Nov. 30, 2017
Income Tax Disclosure [Abstract]
Deferred tax assets	$ 759.0	$ 297.7
Unrecognized tax benefits	25.8	12.3
Business Acquisition [Line Items]
Income tax penalties and interest accrued	52.2	$ 49.7
Income tax penalties and interest expense	1.0
Write down of deferred tax asset resulting from Tax Cuts and Jobs Act	68.6
CalAtlantic Group, Inc.
Business Acquisition [Line Items]
Income tax penalties and interest accrued	$ 1.5