Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012
Guarantor Obligations [Line Items]
Number of non cancelable ground leases	6
Total minimum lease commitments under land leases and operating leases for next five years	$ 1,700,000
Number of communities with indemnification agreements from third parties for potential environmental clean-up costs	3
Comprehensive liabilities insurance deductible per incident	100,000
Property casualty insurance, deductible per incident, maximum	5,000,000
Loan and Construction Completion Guarantee [Member] | Construction Contracts [Member]
Guarantor Obligations [Line Items]
Mortgage loan, maturity date	Jul. 01, 2014
Debt instrument, number of extensions	2
Debt instrument, term of extensions options	1 year
Maximum exposure of the guarantee	70,000,000
Payment Guarantee [Member] | Construction Contracts [Member]
Guarantor Obligations [Line Items]
Maximum exposure of the guarantee	$ 55,700,000