Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets
Land	$ 989,097	$ 989,247
Buildings and improvements	5,956,361	5,911,432
Real estate assets, at cost, total	6,945,458	6,900,679
Accumulated depreciation	(1,855,678)	(1,780,694)
Net operating real estate assets	5,089,780	5,119,985
Properties under development, including land	446,740	486,918
Investments in joint ventures	31,142	33,698
Operating properties held for sale, including land	105,254	0
Discontinued operations held for sale, including land	0	239,063
Total real estate assets	5,672,916	5,879,664
Accounts receivable – affiliates	24,008	25,100
Other assets, net	139,263	116,260
Cash and cash equivalents	341,726	10,617
Restricted cash	21,561	5,971
Total assets	6,199,474	6,037,612
Liabilities
Unsecured notes payable	1,582,077	1,824,930
Secured notes payable	898,723	899,757
Accounts payable and accrued expenses	140,864	133,353
Accrued real estate taxes	46,801	45,223
Distributions payable	69,116	64,275
Other liabilities	117,023	97,814
Total liabilities	2,854,604	3,065,352
Commitments and contingencies (Note 10)
Non-qualified deferred compensation share awards	72,480	79,364
Equity
Common shares of beneficial interest; $0.01 par value per share; 175,000 shares authorized; 100,654 and 100,636 issued; 97,755 and 97,571 outstanding at June 30, 2016 and December 31, 2015, respectively	978	976
Additional paid-in capital	3,673,237	3,662,864
Distributions in excess of net income attributable to common shareholders	(104,004)	(458,577)
Treasury shares, at cost (10,346 and 10,703 common shares at June 30, 2016 and December 31, 2015, respectively)	(373,914)	(386,793)
Accumulated other comprehensive loss	(1,848)	(1,913)
Total common equity	3,194,449	2,816,557
Non-controlling interests	77,941	76,339
Total equity	3,272,390	2,892,896
Total liabilities and equity	$ 6,199,474	$ 6,037,612