CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 258,366	$ 223,753
Adjustments to net income:
Depreciation and amortization	371,755	332,192
Amortization of share-based compensation	10,641	9,204
Non-cash revenue adjustments	(2,783)	(7,583)
Amortization of net premiums on mortgages payable	(1,580)	(2,669)
Amortization of deferred financing costs	6,819	6,510
(Gain) loss on interest rate swaps	(1,228)	5,835
Gain on sales of real estate	(17,689)	(15,283)
Provisions for impairment on real estate	8,072	16,955
Change in assets and liabilities
Accounts receivable and other assets	(2,342)	2,964
Accounts payable, accrued expenses and other liabilities	10,067	7,332
Net cash provided by operating activities	640,098	579,210
CASH FLOWS FROM INVESTING ACTIVITIES
Investment in real estate	(964,719)	(1,027,917)
Improvements to real estate, including leasing costs	(11,834)	(5,295)
Proceeds from sales of real estate	69,486	55,114
Insurance proceeds received	12,746
Collection of loans receivable	92	12,486
Restricted escrow deposits for Section 1031 tax-deferred exchanges and pending acquisitions	(19,452)	(7,757)
Net cash used in investing activities	(913,681)	(973,369)
CASH FLOWS FROM FINANCING ACTIVITIES
Cash distributions to common stockholders	(509,987)	(453,774)
Cash dividends to preferred stockholders	(6,168)	(20,310)
Borrowings on line of credit	1,189,000	3,120,000
Payments on line of credit	(1,651,000)	(2,276,000)
Proceeds from notes and bonds payable issued	711,812
Principal payments on notes payable	(175,000)	(275,000)
Proceeds from mortgages payable		9,963
Principal payments on mortgages payable	(123,524)	(183,697)
Redemption of preferred stock	(408,750)
Proceeds from common stock offerings, net	704,938	383,572
Proceeds from dividend reinvestment and stock purchase plan	67,813	8,174
Procceds from At-the-Market (ATM) program	487,998	85,780
Redemption of common units		(9,026)
Distributions to noncontrolling interests	(1,652)	(1,018)
Debt issuance costs	(6,663)
Other items, including shares withheld upon vesting	(11,455)	(4,998)
Net cash provided by financing activities	267,362	383,666
Net increase (decrease) in cash and cash equivalents	(6,221)	(10,493)
Cash and cash equivalents, beginning of period	9,420	40,294
Cash and cash equivalents, end of period	$ 3,199	$ 29,801