Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
ASSETS
Operating (including $1,731,961 and $1,703,202 of consolidated variable interest entities, respectively)	$ 7,840,664	$ 7,771,981
Construction-in-progress (including $35,359 and $44,896 of consolidated variable interest entities, respectively)	868,193	810,889
Real estate, at cost, total	8,708,857	8,582,870
Less accumulated depreciation and amortization (including $347,041 and $335,735 of consolidated variable interest entities, respectively)	(2,393,380)	(2,357,692)
Net real estate	6,315,477	6,225,178
Cash and cash equivalents	779,901	798,329
Accounts and notes receivable, net	161,249	159,780
Mortgage notes receivable, net	39,879	39,892
Investment in partnerships	12,148	22,128
Operating lease right of use assets	82,721	92,248
Finance lease right of use assets	50,795	51,116
Prepaid expenses and other assets	227,431	218,953
TOTAL ASSETS	7,669,601	7,607,624
Liabilities
Mortgages payable, net (including $397,084 and $413,681 of consolidated variable interest entities, respectively)	466,950	484,111
Notes payable, net	403,081	402,776
Senior notes and debentures, net	3,404,879	3,404,488
Accounts payable and accrued expenses	254,515	228,641
Dividends payable	84,872	83,839
Security deposits payable	20,867	20,388
Operating lease liabilities	63,023	72,441
Finance lease liabilities	72,045	72,049
Other liabilities and deferred credits	156,227	152,424
Total liabilities	4,926,459	4,921,157
Commitments and contingencies (Note 6)
Redeemable noncontrolling interests	138,182	137,720
Shareholders’ equity
Common shares of beneficial interest, $.01 par, 100,000,000 shares authorized, 77,706,466 and 76,727,394 shares issued and outstanding, respectively	781	771
Additional paid-in capital	3,386,917	3,297,305
Accumulated dividends in excess of net income	(1,024,417)	(988,272)
Accumulated other comprehensive loss	(2,300)	(5,644)
Total shareholders’ equity of the Trust	2,520,978	2,464,157
Noncontrolling interests	83,982	84,590
Total shareholders’ equity	2,604,960	2,548,747
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	7,669,601	7,607,624
5.0% Series C Cumulative Redeemable Preferred Shares, (stated at liquidation preference $25,000 per share), 6,000 shares issued and outstanding
Shareholders’ equity
Preferred shares, authorized 15,000,000 shares, $.01 par:	150,000	150,000
5.417% Series 1 Cumulative Convertible Preferred Shares, (stated at liquidation preference $25 per share), 399,896 shares issued and outstanding
Shareholders’ equity
Preferred shares, authorized 15,000,000 shares, $.01 par:	$ 9,997	$ 9,997