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	Dec. 31, 2012	Dec. 31, 2011
Assets acquired
Notes receivable	$ 0	$ 40,000
Other assets	29	18,300
Total Assets acquired	25,029	1,483,000
Liabilities assumed
Mortgage notes payable	0	548,000
Accrued payroll and other operating expenses	376	3,000
Rents and other customer payments received in advance and security deposits	440	5,000
Total Liabilities assumed	816	556,000
Net consideration paid	24,213	927,000
Land
Assets acquired
Property, plant And equipment	4,410	471,500
Depreciable property
Assets acquired
Property, plant And equipment	18,491	855,200
Manufactured homes
Assets acquired
Property, plant And equipment	0	24,000
In-place leases
Assets acquired
Property, plant And equipment	2,099	74,000
Real Estate Investment [Member]
Assets acquired
Property, plant And equipment	$ 25,000	$ 1,424,700