CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Real estate:
Buildings and improvements	$ 10,683,541	$ 11,239,732
Development costs and construction in progress	373,818	447,976
Land	1,655,012	1,785,865
Accumulated depreciation and amortization	(2,750,351)	(2,741,695)
Net real estate	9,962,020	10,731,878
Net investment in direct financing leases	712,570	714,352
Loans receivable, net	38,691	313,326
Investments in and advances to unconsolidated joint ventures	628,607	800,840
Accounts receivable, net of allowance of $4,755 and $4,425, respectively	43,965	40,733
Cash and cash equivalents	91,381	55,306
Restricted cash	30,548	26,897
Intangible assets, net	294,056	410,082
Assets held for sale, net	692,702	417,014
Proceeds receivable from U.K. JV transaction	402,447	0
Other assets, net	554,400	578,033
Total assets	13,451,387	14,088,461
LIABILITIES AND EQUITY
Bank line of credit	545,226	1,017,076
Term loan	222,923	228,288
Senior unsecured notes	6,401,502	6,396,451
Mortgage debt	140,321	144,486
Other debt	93,070	94,165
Intangible liabilities, net	49,976	52,579
Liabilities of assets held for sale, net	10,357	14,031
Accounts payable and accrued liabilities	398,920	401,738
Deferred revenue	172,369	144,709
Total liabilities	8,034,664	8,493,523
Commitments and contingencies
Common stock, $1.00 par value: 750,000,000 shares authorized; 469,829,639 and 469,435,678 shares issued and outstanding, respectively	469,830	469,436
Additional paid-in capital	8,187,385	8,226,113
Cumulative dividends in excess of earnings	(3,509,641)	(3,370,520)
Accumulated other comprehensive income (loss)	(4,080)	(24,024)
Total stockholders' equity	5,143,494	5,301,005
Joint venture partners	96,341	117,045
Non-managing member unitholders	176,888	176,888
Total noncontrolling interests	273,229	293,933
Total equity	5,416,723	5,594,938
Total liabilities and equity	$ 13,451,387	$ 14,088,461