CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 962,501	$ 1,009,708	$ 685,192
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	820,832	831,083	785,725
Amortization of deferred financing costs	8,939	11,670	11,310
Amortization of above/below market lease intangibles	(71)	(71)	4,392
Amortization of discounts and premiums on debt	5,231	11,780	22,781
Amortization of deferred settlements on derivative instruments	35,075	21,176	18,440
Amortization of right-of-use assets	11,682	11,764
Impairment			702
Write-off of pursuit costs	6,869	5,529	4,450
(Income) loss from investments in unconsolidated entities	3,284	(65,945)	3,667
Distributions from unconsolidated entities – return on capital	100	2,621	2,492
Net (gain) loss on sales of real estate properties	(531,807)	(447,637)	(256,810)
Net (gain) loss on sales of land parcels	(34,234)	(2,044)	(987)
Net (gain) loss on debt extinguishment	26,150	13,647	22,110
Realized/unrealized (gain) loss on derivative instruments	50		50
Compensation paid with Company Common Shares	23,174	24,449	27,132
Other operating activities, net	1,805	(287)
Changes in assets and liabilities:
(Increase) decrease in other assets	(53,021)	6,278	4,097
Increase (decrease) in accounts payable and accrued expenses	470	5,116	(1,862)
Increase (decrease) in accrued interest payable	(956)	4,230	4,587
Increase (decrease) in lease liabilities	(2,204)	(2,269)
Increase (decrease) in other liabilities	(8,751)	13,382	16,578
Increase (decrease) in security deposits	(9,582)	2,804	2,249
Net cash provided by operating activities	1,265,536	1,456,984	1,356,295
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in real estate – acquisitions	(48,898)	(1,518,878)	(708,092)
Investment in real estate – development/other	(230,332)	(195,692)	(154,431)
Capital expenditures to real estate	(135,979)	(178,423)	(188,501)
Non-real estate capital additions	(20,100)	(4,955)	(4,505)
Interest capitalized for real estate under development	(10,165)	(6,884)	(6,260)
Proceeds from disposition of real estate, net	1,113,972	1,064,619	691,526
Investments in unconsolidated entities	(5,775)	(9,604)	(6,571)
Distributions from unconsolidated entities – return of capital	1,636	78,262
Purchase of investment securities and other investments	(773)	(269)
Net cash provided by (used for) investing activities	663,586	(771,824)	(376,834)
CASH FLOWS FROM FINANCING ACTIVITIES:
Debt financing costs	(2,923)	(19,812)	(8,583)
Proceeds	519,204	295,771	96,935
Lump sum payoffs	(160,522)	(743,021)	(1,347,939)
Scheduled principal repayments	(7,759)	(6,808)	(6,629)
Proceeds		1,194,468	896,294
Lump sum payoffs	(750,000)	(1,050,000)
Line of credit and commercial paper:
Line of credit proceeds	1,870,000	6,010,000	3,805,000
Line of credit repayments	(1,890,000)	(5,990,000)	(3,805,000)
Commercial paper proceeds	7,450,997	15,944,800	14,030,926
Commercial paper repayments	(8,034,000)	(15,446,150)	(13,831,500)
Proceeds from (payments on) settlement of derivative instruments	(1,240)	(41,616)	18,118
Prepaid finance ground lease		(34,734)
Proceeds from Employee Share Purchase Plan (ESPP)	4,508	3,116	3,879
Proceeds from exercise of options	12,275	77,785	30,655
Payment of offering costs		(991)	(27)
Other financing activities, net	(63)	(80)	(78)
Acquisition of Noncontrolling Interests – Partially Owned Properties			(13)
Contributions – Noncontrolling Interests – Partially Owned Properties	417	7,337	125
Contributions – Noncontrolling Interests – Operating Partnership	13	2	1
Distributions:
Common Shares	(883,938)	(831,111)	(782,122)
Preferred Shares	(3,090)	(3,090)	(3,863)
Noncontrolling Interests – Operating Partnership	(32,403)	(29,615)	(28,226)
Noncontrolling Interests – Partially Owned Properties	(11,719)	(7,078)	(9,753)
Net cash provided by (used for) financing activities	(1,946,393)	(684,474)	(963,910)
Net increase (decrease) in cash and cash equivalents and restricted deposits	(17,271)	686	15,551
Cash and cash equivalents and restricted deposits, beginning of year	116,999	116,313	100,762
Cash and cash equivalents and restricted deposits, end of year	99,728	116,999	116,313
Cash and cash equivalents	42,591	45,753	47,442
Restricted deposits	57,137	71,246	68,871
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	320,854	342,048	358,156
Net cash paid (received) for income and other taxes	(1,038)	(585)	853
Amortization of deferred financing costs:
Investment in real estate, net	(240)	(120)
Other assets	2,338	2,987	2,412
Mortgage notes payable, net	1,815	3,934	4,792
Notes, net	5,026	4,869	4,106
Amortization of discounts and premiums on debt:
Mortgage notes payable, net	2,234	8,618	20,144
Notes, net	2,997	3,162	2,637
Amortization of deferred settlements on derivative instruments:
Other liabilities	(12)	(12)	(12)
Accumulated other comprehensive income	35,087	21,188	18,452
Write-off of pursuit costs:
Investment in real estate, net	6,566	5,451	4,364
Other assets	271	62	53
Accounts payable and accrued expenses	32	16	33
(Income) loss from investments in unconsolidated entities:
Investments in unconsolidated entities	1,995	(67,268)	2,304
Other liabilities	1,289	1,323	1,363
Realized/unrealized (gain) loss on derivative instruments:
Other assets		2,002	(14,977)
Notes, net		2,277	(680)
Other liabilities	1,240	29,486	10,533
Accumulated other comprehensive income	(1,190)	(33,765)	5,174
Investments in unconsolidated entities:
Investments in unconsolidated entities	(4,275)	(7,504)	(4,891)
Other liabilities	(1,500)	(2,100)	(1,680)
Debt financing costs:
Other assets	(231)	(6,909)	(145)
Mortgage notes payable, net	(2,692)	(2,354)	(555)
Notes, net		(10,549)	(7,883)
Right-of-use assets and lease liabilities initial measurement and reclassifications:
Right-of-use assets		(489,517)
Other assets		184,116
Lease liabilities		333,603
Other liabilities		(28,202)
Proceeds from (payments on) settlement of derivative instruments:
Other assets			18,118
Other liabilities	(1,240)	(41,616)
Mortgage Notes Payable, Net [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Net gain (loss) on debt extinguishment	(327)	(3,381)	$ (22,110)
Notes, Net [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Net gain (loss) on debt extinguishment	$ (25,823)	$ (10,266)