Summary of Significant Accounting Policies (Details 3) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Lot Option Purchase Disclosures
Consolidated inventory not owned	$ 39,490,000	$ 51,400,000
Noncontrolling interest	21,824,000	34,223,000	61,806,000
Primary variable interest | Lot option purchase contracts
Lot Option Purchase Disclosures
Consolidated inventory not owned	39,500,000	51,400,000
Cash deposits	17,700,000	17,200,000
Noncontrolling interest	21,800,000	34,200,000
Not primary variable interest | Lot option purchase contracts
Lot Option Purchase Disclosures
Cash deposits and/or letters of credit	22,200,000	22,300,000
Aggregate purchase price	$ 310,100,000	$ 208,500,000