Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Real estate:
Land	$ 721,542	$ 589,359
Construction in progress	64,201	119,992
Buildings, improvements and equipment	4,256,581	3,668,379
Total real estate	5,042,324	4,377,730
Less: accumulated depreciation	(983,759)	(841,801)
Real estate, net	4,058,565	3,535,929
Cash and cash equivalents	8,297	10,782
Cash in escrows	32,604	34,070
Accounts receivable, net	12,142	12,540
Prepaid expenses	15,994	17,662
Deferred charges	16,322	15,079
Other assets	9,282	8,641
Total assets	4,153,206	3,634,703
LIABILITIES AND EQUITY
Mortgage notes payable	2,260,836	2,424,214
Unsecured notes payable	400,000
Exchangeable senior notes		138,218
Unsecured line of credit	2,500	56,500
Accounts payable	20,953	20,935
Accrued interest payable	10,286	11,389
Accrued expenses and other liabilities	29,474	28,730
Security deposits	19,513	19,583
Total liabilities	2,743,562	2,699,569
Commitments and contingencies
Equity:
Preferred stock, $0.01 par value; 10,000,000 shares authorized; no shares issued or outstanding
Common stock, $0.01 par value; 80,000,000 shares authorized; 48,321,305 and 37,949,229 shares issued and outstanding at December 31, 2011 and 2010, respectively	483	379
Excess stock, $0.01 par value; 10,000,000 shares authorized; no shares issued or outstanding
Additional paid-in capital	1,545,563	1,047,325
Distributions in excess of accumulated earnings	(392,378)	(326,811)
Total common stockholders' equity	1,153,668	720,893
Noncontrolling interest	255,976	214,241
Total equity	1,409,644	935,134
Total liabilities and equity	$ 4,153,206	$ 3,634,703