Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Assets
Land	$ 1,047,453	$ 1,003,422
Buildings and improvements	6,237,648	5,890,498
Real estate assets, at cost, total	7,285,101	6,893,920
Accumulated depreciation	(1,914,469)	(1,738,862)
Net operating real estate assets	5,370,632	5,155,058
Properties under development, including land	443,469	527,596
Investments in joint ventures	34,705	36,429
Properties held for sale	13,168	27,143
Total real estate assets	5,861,974	5,746,226
Accounts receivable – affiliates	25,053	25,977
Other assets, net	130,360	124,888
Cash and cash equivalents	10,375	153,918
Restricted cash	6,126	5,898
Total assets	6,033,888	6,056,907
Liabilities
Unsecured notes payable	1,811,739	1,837,911
Secured notes payable	903,468	905,628
Accounts payable and accrued expenses	131,532	157,232
Accrued real estate taxes	57,642	39,149
Distributions payable	64,276	60,386
Other liabilities	96,679	100,058
Total liabilities	$ 3,065,336	$ 3,100,364
Commitments and contingencies (Note 10)
Non-qualified deferred compensation share awards	$ 72,316	$ 68,134
Equity
Common shares of beneficial interest; $0.01 par value per share; 175,000 shares authorized; 100,640 and 100,620 issued; 97,574 and 97,604 outstanding at September 30, 2015 and December 31, 2014, respectively	976	976
Additional paid-in capital	3,660,482	3,667,448
Distributions in excess of net income attributable to common shareholders	(452,257)	(453,777)
Treasury shares, at cost (10,712 and 10,975 common shares at September 30, 2015 and December 31, 2014, respectively)	(387,114)	(396,626)
Accumulated other comprehensive loss	(2,307)	(2,419)
Total common equity	2,819,780	2,815,602
Non-controlling interests	76,456	72,807
Total equity	2,896,236	2,888,409
Total liabilities and equity	$ 6,033,888	$ 6,056,907