SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 2) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Exchange of UPREIT units for shares
Number of shares of UPREIT units	284,180	565,509	528,004
Equity adjustment for exchange of UPREIT units for shares transaction	$ 6,899	$ 11,399	$ 10,234
Cash and Cash Equivalents
Federal Deposit Insurance Corporation limit	250
Accounts Receivable and Allowance for Doubtful Receivables
Minimum period past due to establish allowance for accounts receivable	60 days
Allowance for doubtful resident receivables	2,778	2,869
Deferred Charges
Minimum remaining term for amortization of deferred finance costs	2 months
Maximum remaining term for amortization of deferred finance costs	9 years
Accumulated amortization	11,050	8,231
Continuing operations
Depreciation
Depreciation expense charged to operations	163,024	139,167	121,738
Discontinued operations
Depreciation
Depreciation expense charged to operations	$ 3,355	$ 4,105	$ 4,728
Land improvements | Minimum
Depreciation
Estimated useful lives of assets	3 years
Land improvements | Maximum
Depreciation
Estimated useful lives of assets	20 years
Buildings and improvements | Minimum
Depreciation
Estimated useful lives of assets	3 years
Buildings and improvements | Maximum
Depreciation
Estimated useful lives of assets	40 years
Furniture, fixtures and equipment | Minimum
Depreciation
Estimated useful lives of assets	5 years
Furniture, fixtures and equipment | Maximum
Depreciation
Estimated useful lives of assets	10 years
Computer software
Depreciation
Estimated useful lives of assets	5 years