Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Investment in real estate:
Land	$ 1,023,456	$ 984,224
Land improvements	2,654,169	2,565,299
Buildings and other depreciable property	530,701	495,127
Real Estate Investment Property, at Cost, Total	4,208,326	4,044,650
Accumulated depreciation	(1,031,152)	(948,581)
Net investment in real estate	3,177,174	3,096,069
Cash	51,526	37,126
Notes receivable, net	43,415	45,469
Investment in joint ventures	9,795	8,420
Deferred financing costs, net	19,811	20,620
Deferred commission expense	24,665	22,841
Escrow deposits and other assets	70,744	47,829
Assets of Disposal Group, Including Discontinued Operation	0	119,852
Total Assets	3,397,130	3,398,226
Liabilities:
Mortgage notes payable	1,994,308	2,061,610
Term loan	200,000	200,000
Unsecured lines of credit	0	0
Accrued payroll and other operating expenses	79,020	63,672
Deferred revenue - upfront payments from right-to-use contracts	67,425	62,979
Deferred revenue - right-to-use annual payments	11,456	11,088
Accrued interest payable	9,523	10,500
Rents and other customer payments received in advance and security deposits	53,104	54,017
Distributions payable	22,759	0
Liabilities of Disposal Group, Including Discontinued Operation	0	10,058
Total Liabilities	2,437,595	2,473,924
Stockholders' Equity:
Preferred stock value	0	0
Common stock, $0.01 par value	834	832
Paid-in capital	1,021,694	1,012,514
Distributions in excess of accumulated earnings	267,415	287,652
Accumulated other comprehensive loss	(1,357)	(2,590)
Total Stockholders' Equity	889,900	859,248
Non-controlling interests - Common OP Units	69,635	65,054
Total Equity	959,535	924,302
Total Liabilities and Equity	3,397,130	3,398,226
Cumulative Series C Six Point Seven Five Percent Redeemable Perpetual Preferred Stock [Domain]
Stockholders' Equity:
Preferred stock value	$ 136,144	$ 136,144