Consolidated Balance Sheets (USD $)	Sep. 30, 2012	Dec. 31, 2011
Investment in real estate:
Land	$ 1,016,004,000	$ 1,018,521,000
Land improvements	2,601,980,000	2,591,225,000
Buildings and other depreciable property	508,177,000	469,627,000
Real Estate Investment Property, at Cost, Total	4,126,161,000	4,079,373,000
Accumulated depreciation	(937,078,000)	(813,926,000)
Net investment in real estate	3,189,083,000	3,265,447,000
Cash and cash equivalents	147,868,000	70,460,000
Notes receivable, net	56,056,000	64,239,000
Investment in joint ventures	8,531,000	8,557,000
Rent and other customer receivables, net	1,098,000	1,155,000
Deferred financing costs, net	21,919,000	23,039,000
Inventory	2,246,000	2,948,000
Deferred commission expense	21,861,000	19,687,000
Escrow deposits and other assets	48,463,000	40,569,000
Total Assets	3,497,125,000	3,496,101,000
Liabilities:
Mortgage notes payable	2,084,203,000	2,084,683,000
Term loan	200,000,000	200,000,000
Unsecured lines of credit	0	0
Accrued payroll and other operating expenses	76,801,000	62,062,000
Deferred revenue - upfront payments from right-to-use contracts	60,965,000	56,285,000
Deferred revenue - right-to-use annual payments	12,100,000	11,877,000
Accrued interest payable	10,305,000	10,737,000
Rents and other customer payments received in advance and security deposits	51,560,000	54,234,000
Distributions payable	20,415,000	16,943,000
Total Liabilities	2,516,349,000	2,496,821,000
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	0	200,000,000
Stockholders' Equity:
Preferred stock value	0	0
Common stock, $0.01 par value	415,000	412,000
Paid-in capital	1,010,154,000	998,483,000
Distributions in excess of accumulated earnings	(293,790,000)	(270,021,000)
Accumulated other comprehensive loss	(3,013,000)	(2,547,000)
Total Stockholders' Equity	913,766,000	726,327,000
Non-controlling interests - Common OP Units	67,010,000	72,953,000
Total Equity	980,776,000	799,280,000
Total Liabilities and Equity	3,497,125,000	3,496,101,000
8.034% Series A Cumulative Redeemable Perpetual Preferred Stock
Stockholders' Equity:
Preferred stock value	63,856,000	0
Additional Paid-in Capital
Stockholders' Equity:
Total Equity	1,010,154,000	998,483,000
Accumulated Distributions in Excess of Net Income [Member]
Stockholders' Equity:
Total Equity	(293,790,000)	(270,021,000)
Accumulated Other Comprehensive Income (Loss) [Member]
Stockholders' Equity:
Total Equity	(3,013,000)	(2,547,000)
Non-controlling interests - Common OP Units
Stockholders' Equity:
Total Equity	67,010,000	72,953,000
Common Stock
Stockholders' Equity:
Total Equity	$ 415,000	$ 412,000