CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Real estate:
Land	$ 3,346,202	$ 3,315,521
Buildings and improvements	11,460,239	11,230,813
Furniture, fixtures and equipment	357,527	343,802
Total Capitalized Cost	15,163,968	14,890,136
Less accumulated depreciation	(2,608,172)	(2,503,902)
Net operating real estate	12,555,796	12,386,234
Construction in progress, including land	1,646,361	1,583,120
Land held for development	250,204	300,364
Operating real estate assets held for sale, net		14,491
Total real estate, net	14,452,361	14,284,209
Cash and cash equivalents	386,190	281,541
Cash in escrow	90,663	98,481
Resident security deposits	27,232	26,672
Investments in unconsolidated real estate entities	353,510	367,866
Deferred financing costs, net	42,181	40,677
Deferred development costs	34,305	31,592
Prepaid expenses and other assets	183,797	197,105
Total assets	15,570,239	15,328,143
LIABILITIES AND EQUITY
Unsecured notes, net	2,844,917	2,594,709
Mortgage notes payable	3,536,881	3,550,682
Dividends payable	150,309	138,476
Payables for construction	94,133	94,472
Accrued expenses and other liabilities	241,148	243,045
Accrued interest payable	33,285	43,353
Resident security deposits	46,493	45,485
Liabilities related to real estate assets held for sale		874
Total liabilities	6,947,166	6,711,096
Redeemable noncontrolling interests	16,002	17,320
Equity:
Preferred stock, $0.01 par value; $25 liquidation preference; 50,000,000 shares authorized at both March 31, 2014 and December 31, 2013; zero shares issued and outstanding at March 31, 2014 and December 31, 2013, respectively
Common stock, $0.01 par value; 280,000,000 shares authorized at March 31, 2014 and December 31, 2013; 129,572,864 and 129,416,695 shares issued and outstanding at March 31, 2014 and December 31, 2013, respectively	1,296	1,294
Additional paid-in capital	9,002,260	8,988,723
Accumulated earnings less dividends	(353,029)	(345,254)
Accumulated other comprehensive loss	(47,058)	(48,631)
Total stockholders' equity	8,603,469	8,596,132
Noncontrolling interest	3,602	3,595
Total equity	8,607,071	8,599,727
Total liabilities and equity	$ 15,570,239	$ 15,328,143