CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Real estate properties:
Land	$ 146,700	$ 191,775
Buildings and improvements	1,117,446	1,555,836
Total real estate properties, at cost, gross	1,264,146	1,747,611
Accumulated depreciation	(387,888)	(450,718)
Total real estate properties, at cost, net	876,258	1,296,893
Assets held for sale	0	97,688
Acquired real estate leases, net	2,946	23,847
Cash and cash equivalents	2,507,117	2,351,693
Marketable securities	248,275	276,928
Restricted cash	8,419	8,897
Rents receivable, net of allowance for doubtful accounts of $5,101 and $4,771, respectively	57,347	93,436
Other assets, net	76,512	87,563
Total assets	3,776,874	4,236,945
LIABILITIES AND EQUITY
Senior unsecured debt, net	248,048	815,984
Mortgage notes payable, net	31,964	32,594
Liabilities related to properties held for sale	0	1,840
Accounts payable, accrued expenses and other	44,380	74,956
Rent collected in advance	10,173	11,076
Total liabilities	334,565	936,450
Shareholders' equity:
Common shares of beneficial interest, $0.01 par value: 350,000,000 shares authorized; 121,482,673 and 124,217,616 shares issued and outstanding, respectively	1,215	1,242
Additional paid in capital	4,300,822	4,380,313
Cumulative net income	2,822,793	2,596,259
Cumulative other comprehensive loss	(1,469)	(95)
Cumulative common distributions	(3,111,868)	(3,111,868)
Cumulative preferred distributions	(689,742)	(685,748)
Total shareholders’ equity	3,441,014	3,299,366
Noncontrolling interest	1,295	1,129
Total equity	3,442,309	3,300,495
Total liabilities and equity	3,776,874	4,236,945
Series D
Shareholders' equity:
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
Total equity	$ 119,263	$ 119,263