CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited) - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	Total	PREFERRED SHARES	COMMON SHARES, $0.01 PAR VALUE	PAID IN CAPITAL	RETAINED EARNINGS	ACCUMULATED OTHER COMPREHENSIVE (LOSS)	OPERATING PARTNERSHIP	PARTIALLY OWNED PROPERTIES
Balance, beginning of year at Dec. 31, 2016	$ 10,229,078	$ 37,280	$ 3,659	$ 8,758,422	$ 1,543,626	$ (113,909)
Balance, beginning of year at Dec. 31, 2016	231,906						$ 221,297	$ 10,609
COMMON SHARES, $0.01 PAR VALUE
Conversion of OP Units into Common Shares			11	14,706			(14,717)
Exercise of share options			3	12,964
Employee Share Purchase Plan (ESPP)			1	2,962
Restricted shares			1	7,488
Share options				6,384
ESPP discount				586
PAID IN CAPITAL
Conversion of OP Units into Common Shares			11	14,706			(14,717)
Exercise of share options			3	12,964
Employee Share Purchase Plan (ESPP)			1	2,962
Share-based employee compensation expense
Offering costs				(36)
Supplemental Executive Retirement Plan (SERP)				(594)
Change in market value of Redeemable Noncontrolling Interests – Operating Partnership	(29,551)			29,551
Adjustment for Noncontrolling Interests ownership in Operating Partnership				16,306			(16,306)
RETAINED EARNINGS
Net income attributable to controlling interests	478,012				478,012
Common Share distributions					(555,071)
Preferred Share distributions					(2,318)
Accumulated other comprehensive income – derivative instruments:
Unrealized holding gains (losses) arising during the period	5,216					5,216
Losses reclassified into earnings from other comprehensive income	(14,019)					14,019
OPERATING PARTNERSHIP
Conversion of OP Units into Common Shares			11	14,706			(14,717)
Equity compensation associated with Noncontrolling Interests							8,200
Net income	498,297
Distributions to Noncontrolling Interests							(20,073)	(6,913)
Change in carrying value of Redeemable Noncontrolling Interests - Operating Partnership	(32,000)						32,000
Adjustment for Noncontrolling Interests ownership in Operating Partnership				16,306			(16,306)
Net income attributable to Noncontrolling Interests	17,931						17,931	2,354
PARTIALLY OWNED PROPERTIES
Net income	498,297
Distributions to Noncontrolling Interests							(20,073)	(6,913)
Net income attributable to Noncontrolling Interests	17,931						17,931	2,354
Contributions – Noncontrolling Interests – Partially Owned Properties	125							125
Balance, end of period at Sep. 30, 2017	10,259,269	$ 37,280	$ 3,675	$ 8,848,739	$ 1,464,249	$ (94,674)
Balance, end of period at Sep. 30, 2017	$ 234,507						$ 228,332	$ 6,175