CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited) - 6 months ended Jun. 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	14,611			(14,622)
Exercise of share options			2	8,141
Restricted shares			1	5,381
Share options				5,979
ESPP discount				414
PAID IN CAPITAL
Conversion of OP Units into Common Shares			11	14,611			(14,622)
Exercise of share options			2	8,141
Employee Share Purchase Plan (ESPP)				2,111
Share-based employee compensation expense
Offering costs				(36)
Supplemental Executive Retirement Plan (SERP)				(666)
Change in market value of Redeemable Noncontrolling Interests – Operating Partnership	(30,351)			30,351
Adjustment for Noncontrolling Interests ownership in Operating Partnership				14,096			(14,096)
RETAINED EARNINGS
Net income attributable to controlling interests	339,783				339,783
Common Share distributions					(369,964)
Preferred Share distributions					(1,546)
Accumulated other comprehensive income – derivative instruments:
Unrealized holding gains (losses) arising during the period	3,507					3,507
Losses reclassified into earnings from other comprehensive income	(9,251)					9,251
OPERATING PARTNERSHIP
Conversion of OP Units into Common Shares			11	14,611			(14,622)
Equity compensation associated with Noncontrolling Interests							5,869
Net income	354,101
Distributions to Noncontrolling Interests							(13,386)	(5,984)
Change in carrying value of Redeemable Noncontrolling Interests – Operating Partnership	(31,222)						31,222
Adjustment for Noncontrolling Interests ownership in Operating Partnership				14,096			(14,096)
Net income attributable to Noncontrolling Interests	12,765						12,765	1,553
PARTIALLY OWNED PROPERTIES
Net income	354,101
Distributions to Noncontrolling Interests							(13,386)	(5,984)
Net income attributable to Noncontrolling Interests	12,765						12,765	1,553
Contributions – Noncontrolling Interests – Partially Owned Properties	125							125
Balance, end of period at Jun. 30, 2017	10,290,505	$ 37,280	$ 3,673	$ 8,838,804	$ 1,511,899	$ (101,151)
Balance, end of period at Jun. 30, 2017	$ 235,352						$ 229,049	$ 6,303