CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Real estate properties:
Land	$ 269,062	$ 286,186
Buildings and improvements	2,395,748	2,570,704
Total real estate properties, at cost, gross	2,664,810	2,856,890
Accumulated depreciation	(705,000)	(755,255)
Total real estate properties, at cost, net	1,959,810	2,101,635
Properties held for sale	64,396	0
Acquired real estate leases, net	45,482	48,281
Cash and cash equivalents	1,888,537	2,094,674
Marketable securities	275,597	0
Restricted cash	6,155	6,532
Rents receivable, net of allowance for doubtful accounts of $4,593 and $5,105, respectively	152,081	152,031
Other assets, net	126,698	122,922
Total assets	4,518,756	4,526,075
LIABILITIES AND EQUITY
Senior unsecured debt, net	1,064,450	1,063,950
Mortgage notes payable, net	77,178	77,717
Liabilities related to properties held for sale	1,013	0
Accounts payable and accrued expenses	62,518	95,395
Assumed real estate lease obligations, net	1,630	1,946
Rent collected in advance	18,485	18,460
Security deposits	6,957	8,160
Total liabilities	1,232,231	1,265,628
Preferred shares of beneficial interest, $0.01 par value: 50,000,000 shares authorized;
Series D preferred shares; 6 1/2% cumulative convertible; 4,915,196 shares issued and outstanding, aggregate liquidation preference of $122,880	119,263	119,263
Common shares of beneficial interest, $0.01 par value: 350,000,000 shares authorized; 124,064,195 and 123,994,465 shares issued and outstanding, respectively	1,240	1,240
Additional paid in capital	4,367,190	4,363,177
Cumulative net income	2,590,417	2,566,603
Cumulative other comprehensive loss	(1,002)	(208)
Cumulative common distributions	(3,111,868)	(3,111,868)
Cumulative preferred distributions	(679,757)	(677,760)
Total shareholders’ equity	3,285,483	3,260,447
Noncontrolling interest	1,042	0
Total equity	3,286,525	3,260,447
Total liabilities and equity	$ 4,518,756	$ 4,526,075