Variable Interest Entities (Narrative) (Details) $ in Millions	3 Months Ended
	Feb. 28, 2019 USD ($) joint_venture entity	Nov. 30, 2018 USD ($) joint_venture
Variable Interest Entity [Line Items]
Number of entities consolidated | entity	3
VIE assets consolidated	$ 260.2
VIE liabilities consolidated	228.6
Consolidated VIEs assets	1,000.0	$ 666.2
Consolidated VIEs liabilities	$ 528.4	$ 242.5
Number of unconsolidated entities debt repayment guarantee | joint_venture	3	4
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Decrease in consolidated inventory	$ 93.0
Variable Interest Entity, Not Primary Beneficiary Including Third Parties
Variable Interest Entity [Line Items]
Non-refundable option deposits and pre-acquisition costs	226.4	$ 209.5
Financial Standby Letters of Credit | Variable Interest Entity, Not Primary Beneficiary Including Third Parties
Variable Interest Entity [Line Items]
Letters of credit outstanding	69.2	72.4
Multifamily | Equity Commitments | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Obligations to make capital contributions to VIEs	(218.2)	(237.0)
Multifamily | Financial Standby Letters of Credit | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Obligations to make capital contributions to VIEs	(1.9)	(4.6)
Homebuilding | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Obligations to make capital contributions to VIEs	$ (50.2)	$ (54.8)
Number of unconsolidated entities debt repayment guarantee | joint_venture	1