Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended												12 Months Ended					12 Months Ended				12 Months Ended									12 Months Ended						1 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2009	Mar. 31, 2009	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Aug. 14, 2008 Property	Dec. 31, 2011 Maximum	Dec. 31, 2011 Minimum	Dec. 31, 2011 Natural Disasters and Other Casualty Events Property	Dec. 31, 2010 Fair Value, Inputs, Level 1 US Treasury Bill Securities	Dec. 31, 2010 Fair Value, Inputs, Level 2 US Treasury Bill Securities	Dec. 31, 2011 Florida	Dec. 31, 2010 Florida	Dec. 31, 2011 Arizona	Dec. 31, 2010 Arizona	Dec. 31, 2011 California	Dec. 31, 2010 California	Dec. 31, 2011 Chattel Loans Year	Dec. 31, 2011 Chattel Loans Maximum Year	Dec. 31, 2011 Discontinued Operation	Dec. 31, 2011 Buildings and structural and land improvements Year	Dec. 31, 2011 Building Improvements Year	Dec. 31, 2011 Furniture, Fixtures and Equipment Year	Dec. 31, 2011 Real Estate Year	Dec. 31, 2011 In-place leases Year	Dec. 31, 2011 Preferred Stock	Mar. 31, 2011 8.034% Series A Cumulative Redeemable Perpetual Preferred Stock	Dec. 31, 2011 8.034% Series A Cumulative Redeemable Perpetual Preferred Stock	Mar. 04, 2011 8.034% Series A Cumulative Redeemable Perpetual Preferred Stock	Dec. 31, 2010 8.034% Series A Cumulative Redeemable Perpetual Preferred Stock
Significant Accounting Policies [Line Items]
Investment percentage to apply cost method accounting, maximum																	5.00%
Estimated useful life																															30	10	5	20	1
Rental units, salvage value	40.00%												40.00%																					40.00%
Intangible assets and goodwill	$ 12,100,000				$ 15,900,000								$ 12,100,000	$ 15,900,000
Disposal of Intangable assets																														3,500,000
Intangible assets	4,300,000				8,100,000								4,300,000	8,100,000
Goodwill	7,800,000				7,800,000								7,800,000	7,800,000
Accumulated amortization of identified intangible assets	1,200,000				1,600,000								1,200,000	1,600,000																2,000,000
Amortization expense for identified intangible assets													1,900,000	900,000
Goodwill impairment														3,635,000
Cash and cash equivalents, restricted cash	4,200,000				3,000,000								4,200,000	3,000,000
Accumulated amortization for deferred financing costs	15,100,000				12,600,000								15,100,000	12,600,000
Non-Controlling Interests - Common OP Units	4,103,067				4,431,420				4,914,040				4,103,067	4,431,420	4,914,040
Net investment in real estate U.S federal tax basis	2,600,000,000												2,600,000,000
Net investment in notes receivable U.S federal tax basis	75,700,000												75,700,000
Loans receivable, amortization term																												15	29
Estimated claims from hurricanes																			21,000,000
Number of properties suffered from hurricanes damage																82			70
Proceeds from insurance carriers													14,700,000
Gain on insurance recovery, net													2,600,000	300,000	1,600,000
Contingent legal fees													900,000	200,000	300,000
Held to maturity securities at fair value																				52,300,000
Mortgage notes payable, fair value																					2,200,000,000
Provision for uncollectable rents receivable	4,400,000				3,000,000								4,400,000	3,000,000
Rental income recognition period																	1 year
Percentage of company revenue																						38.50%	37.60%	10.80%	11.50%	17.80%	19.40%
Deferred revenue, estimated period of recognition																	31 years	1 year
Right-to-use properties contract, term																		1 year
Right-to-use contract, description of amortization method													For example, the Company has currently estimated that 7.9% of customers who enter a new right-to-use contract will terminate their contract after five years. Therefore, the upfront nonrefundable payments from 7.9% of the contracts entered in any particular period are amortized on a straight-line basis over a period of five years as five years is the estimated customer life for 7.9% of the Company's customers who enter a contract.
Estimated termination period for 7.9% of the new customers who enter into a Right-to-use contract													5 years
Right-to-use contract, amortization period for the upfront payments from the 7.9% of customers	5 years												5 years
Deferred revenue, estimated period of recognition													Right-to-use annual payments by customers under the terms of the right-to-use contracts are deferred and recognized ratably over the one-year period in which the services are provided.
Private REIT Subsidiaries preferred stock	72,953,000				33,128,000								72,953,000	33,128,000																						500,000
Cumulative Redeemable Preferred Stock, shares issued																																						8,000,000	8,000,000	0
Cumulative Redeemable Preferred Stock, par value																																						$ 0.01	$ 0.01	$ 0.01
Cumulative Redeemable Preferred Stock, liquidation preference per share																																							$ 25.00
Cumulative Redeemable Preferred Stock, dividend rate																																					8.034%
Cumulative Redeemable Preferred Stock, conversion price per share																																							$ 24.75
Cumulative Redeemable Preferred Stock, redemption price per share																																							$ 25.00
Perpetual Preferred OP United conversion													$ (200,000,000)
Quarterly distribution paid per common share	$ 0.3750	$ 0.3750	$ 0.3750	$ 0.3750	$ 0.3000	$ 0.3000	$ 0.3000	$ 0.3000	$ 0.3000	$ 0.3000	$ 0.2500	$ 0.2500