Estimated Fair Value of Assets Acquired and Liabilities Assumed in Acquisition Determined using Level Two and Level Three Inputs (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Assets acquired
Notes receivable	$ 40,000
Other assets	18,300
Total Assets acquired	1,483,000
Liabilities assumed
Mortgage notes payable	548,000
Accrued payroll and other operating expenses	3,000
Rents and other customer payments received in advance and security deposits	5,000
Total Liabilities assumed	556,000
Net consideration paid	927,000
Land
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment	471,500
Depreciable property
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment	855,200
Manufactured homes
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment	24,000
In-place leases
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment	74,000
Real Estate Investment [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment	$ 1,424,700