Financial Instruments and Fair Value Disclosures - (Narrative) (Details) $ in Millions	9 Months Ended
	Aug. 31, 2019 USD ($) community homes	Aug. 31, 2018 USD ($) community homes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Active communities | community	1,295	1,307
Number of communities assessed for impairment | community	47	15
Number of homesites assessed for impairment | homes	2,554	843
Inventory with potential indicators of impairment	$ 331.2	$ 219.3
Valuation adjustments to inventory	$ 2.0	$ 29.4
Number of homes impaired | homes	110	688
Number of communities impaired | community	1	5
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Carrying value of homesites impaired	$ 6.2	$ 56.5
Commitments to Sell MBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Open commitments	$ 1,600.0
Mortgage Prepayment Rate | Level 3 | Financial Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Unobservable inputs for valuation of mortgage servicing rights	0.201
Discount Rate | Level 3 | Financial Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Unobservable inputs for valuation of mortgage servicing rights	0.124
Delinquency Rate | Level 3 | Financial Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Unobservable inputs for valuation of mortgage servicing rights	0.084