CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 170,294	$ 146,551
Adjustments to net income:
Depreciation and amortization	244,186	218,275
Amortization of share-based compensation	7,215	6,552
Non-cash revenue adjustments	(1,564)	(5,279)
Amortization of net premiums on mortgages payable	(1,240)	(1,855)
Amortization of deferred financing costs	4,684	4,384
(Gain) loss on interest rate swaps	(859)	7,886
Gain on sales of real estate	(13,371)	(10,948)
Provisions for impairment on real estate	7,706	8,192
Change in assets and liabilities
Accounts receivable and other assets	1,946	6,946
Accounts payable, accrued expenses and other liabilities	41,620	(19,277)
Net cash provided by operating activities	460,617	361,427
CASH FLOWS FROM INVESTING ACTIVITIES
Investment in real estate	(696,116)	(618,340)
Improvements to real estate, including leasing costs	(9,232)	(2,934)
Proceeds from sales of real estate	44,005	35,020
Collection of loans receivable	61	12,457
Restricted escrow deposits for Section 1031 tax-deferred exchanges and pending acquisitions	(3,983)	(17,291)
Net cash used in investing activities	(665,265)	(591,088)
CASH FLOWS FROM FINANCING ACTIVITIES
Cash distributions to common stockholders	(335,380)	(298,581)
Cash dividends to preferred stockholders	(6,168)	(13,540)
Borrowings on line of credit	772,000	2,244,000
Payments on line of credit	(1,244,000)	(1,970,000)
Proceeds from notes and bonds payable issued	711,812
Principal payments on mortgages payable	(86,515)	(181,333)
Redemption of preferred stock	(408,750)
Proceeds from common stock offerings, net	704,938	383,525
Proceeds from dividend reinvestment and stock purchase plan	59,649	5,806
Procceds from At-the-Market (ATM) program	52,442	44,565
Distributions to noncontrolling interests	(887)	(747)
Debt issuance costs	(6,663)
Other items, including shares withheld upon vesting	(6,305)	(3,885)
Net cash provided by financing activities	206,173	209,810
Net increase (decrease) in cash and cash equivalents	1,525	(19,851)
Cash and cash equivalents, beginning of period	9,420	40,294
Cash and cash equivalents, end of period	$ 10,945	$ 20,443