Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Assets
Land	$ 1,034,649	$ 1,003,422
Buildings and improvements	6,134,510	5,890,498
Real estate assets, at cost, total	7,169,159	6,893,920
Accumulated depreciation	(1,860,923)	(1,738,862)
Net operating real estate assets	5,308,236	5,155,058
Properties under development, including land	488,565	527,596
Investments in joint ventures	35,731	36,429
Properties held for sale	0	27,143
Total real estate assets	5,832,532	5,746,226
Accounts receivable – affiliates	25,855	25,977
Other assets, net	120,082	124,888
Cash and cash equivalents	16,508	153,918
Restricted cash	5,791	5,898
Total assets	6,000,768	6,056,907
Liabilities
Unsecured notes payable	1,770,491	1,837,911
Secured notes payable	904,196	905,628
Accounts payable and accrued expenses	128,532	157,232
Accrued real estate taxes	43,905	39,149
Distributions payable	64,253	60,386
Other liabilities	100,515	100,058
Total liabilities	$ 3,011,892	$ 3,100,364
Commitments and contingencies (Note 10)
Non-qualified deferred compensation share awards	$ 69,791	$ 68,134
Equity
Common shares of beneficial interest; $0.01 par value per share; 175,000 shares authorized; 100,641 and 100,620 issued; 97,568 and 97,604 outstanding at June 30, 2015 and December 31, 2014, respectively	976	976
Additional paid-in capital	3,657,537	3,667,448
Distributions in excess of net income attributable to common shareholders	(426,614)	(453,777)
Treasury shares, at cost (10,714 and 10,975 common shares at June 30, 2015 and December 31, 2014, respectively)	(387,172)	(396,626)
Accumulated other comprehensive loss	(2,345)	(2,419)
Total common equity	2,842,382	2,815,602
Non-controlling interests	76,703	72,807
Total equity	2,919,085	2,888,409
Total liabilities and equity	$ 6,000,768	$ 6,056,907