Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Assets
Land	$ 998,519	$ 989,247
Buildings and improvements	5,978,843	5,911,432
Real estate assets, at cost, total	6,977,362	6,900,679
Accumulated depreciation	(1,841,107)	(1,780,694)
Net operating real estate assets	5,136,255	5,119,985
Properties under development, including land	489,730	486,918
Investments in joint ventures	32,568	33,698
Properties held for sale, including land	238,417	239,063
Total real estate assets	5,896,970	5,879,664
Accounts receivable – affiliates	24,011	25,100
Other assets, net	107,161	116,260
Cash and cash equivalents	6,935	10,617
Restricted cash	5,378	5,971
Total assets	6,040,455	6,037,612
Liabilities
Unsecured notes payable	1,866,502	1,824,930
Secured notes payable	899,315	899,757
Accounts payable and accrued expenses	140,991	133,353
Accrued real estate taxes	25,499	45,223
Distributions payable	69,020	64,275
Other liabilities	86,423	97,814
Total liabilities	$ 3,087,750	$ 3,065,352
Commitments and contingencies (Note 10)
Non-qualified deferred compensation share awards	$ 88,550	$ 79,364
Equity
Common shares of beneficial interest; $0.01 par value per share; 175,000 shares authorized; 100,635 and 100,636 issued; 97,455 and 97,571 outstanding at March 31, 2016 and December 31, 2015, respectively	975	976
Additional paid-in capital	3,658,372	3,662,864
Distributions in excess of net income attributable to common shareholders	(491,275)	(458,577)
Treasury shares, at cost (10,460 and 10,703 common shares at March 31, 2016 and December 31, 2015, respectively)	(378,032)	(386,793)
Accumulated other comprehensive loss	(1,881)	(1,913)
Total common equity	2,788,159	2,816,557
Non-controlling interests	75,996	76,339
Total equity	2,864,155	2,892,896
Total liabilities and equity	$ 6,040,455	$ 6,037,612