Commitment and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012
Financial Instruments Owned and Pledged as Collateral [Line Items]
Surety bonds, issued and outstanding	$ 56.0	$ 56.0
Letters of credit, issued and outstanding	18.0	18.0
Legal Recoveries [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Legal recoveries	2.2	2.2
Significant legal recoveries [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Legal recoveries	9.8	9.8
Option Contracts [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Letters of credit, issued and outstanding	3.3	3.3
Cash deposits	6.2	6.2
Right to acquire lots under options contracts, number of lots	1,450	1,450
HomeAmerican [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Letters of credit, issued and outstanding	7.1	7.1
Estimated cost to related to bonds	27.4	27.4
Estimated cost to related to letters of credit	$ 3.1	$ 3.1