CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Series K Preferred Stock [Member]	PREFERRED SHARES	COMMON SHARES, $0.01 PAR VALUE	PAID IN CAPITAL	RETAINED EARNINGS	ACCUMULATED OTHER COMPREHENSIVE (LOSS)	OPERATING PARTNERSHIP	Partially Owned [Domain]
Balance, beginning of year at Dec. 31, 2013			$ 50,000	$ 3,605	$ 8,561,500	$ 2,047,258	$ (155,162)
Balance, beginning of year at Dec. 31, 2013								$ 211,412	$ 126,583
PREFERRED SHARES
Partial redemption of 8.29% Series K Cumulative Redeemable			0
Preferred Stock Preference Units Dividend Rate Percentage		8.29%
COMMON SHARES, $0.01 PAR VALUE
Conversion of OP Units into Common Shares				1	2,364			(2,365)
Exercise of share options				21	82,552
Employee Share Purchase Plan (ESPP)				0	3,392
Restricted shares				2	9,902
PAID IN CAPITAL
Conversion of OP Units into Common Shares				1	2,364			(2,365)
Exercise of share options				21	82,552
Employee Share Purchase Plan (ESPP)				0	3,392
Conversion of restricted shares to restricted units					0			0
Share-based employee compensation expense:
Restricted shares				2	9,902
Share options					7,349
ESPP discount					859
Common Shares repurchsed and retired					(1,777)
Offering costs					(41)
Supplemental Executive Retirement Plan (SERP)					7,374
Acquisition of Noncontrolling Interests – Partially Owned Properties					(2,308)				(2,244)
Change in market value of Redeemable Noncontrolling Interests – Operating Partnership	$ 139,818				(139,818)
Adjustment for Noncontrolling Interests ownership in Operating Partnership					4,992			(4,992)
RETAINED EARNINGS
Net income attributable to controlling interests	631,308					631,308
Common Share distributions						(723,782)
Preferred Share distributions						(4,145)
Premium on redemption of Preferred Shares – cash charge						0
Accumulated other comprehensive income (loss) – derivative instruments:
Unrealized holding (losses) gains arising during the year	(33,306)						(33,306)
Losses reclassified into earnings from other comprehensive income	(16,868)						16,868
Accumulated other comprehensive income (loss) – foreign currency:
Currency translation adjustments arising during the year	(552)						(552)
OPERATING PARTNERSHIP
Issuance of restricted units to Noncontrolling Interests								3
Conversion of OP Units into Common Shares				1	2,364			(2,365)
Conversion of restricted shares to restricted units					0			0
Equity compensation associated with Noncontrolling Interests								11,969
Net income attributable to Noncontrolling Interests	658,683							24,831	2,544
Distributions to Noncontrolling Interests								(28,676)	(7,827)
Change in carrying value of Redeemable Noncontrolling Interests – Operating Partnership	(2,229)							2,229
Adjustment for Noncontrolling Interests ownership in Operating Partnership					4,992			(4,992)
PARTIALLY OWNED PROPERTIES
Net income attributable to Noncontrolling Interests	658,683							24,831	2,544
Contributions – Noncontrolling Interests – Partially Owned Properties	5,684								5,684
Distributions to Noncontrolling Interests								(28,676)	(7,827)
Acquisition of Noncontrolling Interests – Partially Owned Properties					(2,308)				(2,244)
Deconsolidation of previously consolidated Noncontrolling Interests									0
Other									169
Balance, end of year at Dec. 31, 2014			50,000	3,629	8,536,340	1,950,639	(172,152)
Balance, end of year at Dec. 31, 2014								214,411	124,909
PREFERRED SHARES
Partial redemption of 8.29% Series K Cumulative Redeemable			(12,720)
Preferred Stock Preference Units Dividend Rate Percentage		8.29%
COMMON SHARES, $0.01 PAR VALUE
Conversion of OP Units into Common Shares				2	4,964			(4,966)
Exercise of share options				14	59,494
Employee Share Purchase Plan (ESPP)				1	4,403
Restricted shares				2	15,064
PAID IN CAPITAL
Conversion of OP Units into Common Shares				2	4,964			(4,966)
Exercise of share options				14	59,494
Employee Share Purchase Plan (ESPP)				1	4,403
Conversion of restricted shares to restricted units					(70)			70
Share-based employee compensation expense:
Restricted shares				2	15,064
Share options					3,756
ESPP discount					884
Common Shares repurchsed and retired					0
Offering costs					(79)
Supplemental Executive Retirement Plan (SERP)					1,380
Acquisition of Noncontrolling Interests – Partially Owned Properties					0				0
Change in market value of Redeemable Noncontrolling Interests – Operating Partnership	64,378				(64,378)
Adjustment for Noncontrolling Interests ownership in Operating Partnership					10,607			(10,607)
RETAINED EARNINGS
Net income attributable to controlling interests	870,120					870,120
Common Share distributions						(804,825)
Preferred Share distributions						(3,357)
Premium on redemption of Preferred Shares – cash charge						(3,486)
Accumulated other comprehensive income (loss) – derivative instruments:
Unrealized holding (losses) gains arising during the year	2,219						2,219
Losses reclassified into earnings from other comprehensive income	(18,244)						18,244
Accumulated other comprehensive income (loss) – foreign currency:
Currency translation adjustments arising during the year	(327)						(327)
OPERATING PARTNERSHIP
Issuance of restricted units to Noncontrolling Interests								3
Conversion of OP Units into Common Shares				2	4,964			(4,966)
Conversion of restricted shares to restricted units					(70)			70
Equity compensation associated with Noncontrolling Interests								21,503
Net income attributable to Noncontrolling Interests	908,018							34,241	3,657
Distributions to Noncontrolling Interests								(31,604)	(6,608)
Change in carrying value of Redeemable Noncontrolling Interests – Operating Partnership	1,672							(1,672)
Adjustment for Noncontrolling Interests ownership in Operating Partnership					10,607			(10,607)
PARTIALLY OWNED PROPERTIES
Net income attributable to Noncontrolling Interests	908,018							34,241	3,657
Contributions – Noncontrolling Interests – Partially Owned Properties	0								0
Distributions to Noncontrolling Interests								(31,604)	(6,608)
Acquisition of Noncontrolling Interests – Partially Owned Properties					0				0
Deconsolidation of previously consolidated Noncontrolling Interests									(117,350)
Other									0
Balance, end of year at Dec. 31, 2015	10,470,368		37,280	3,648	8,572,365	2,009,091	(152,016)
Balance, end of year at Dec. 31, 2015	10,696,355							221,379	4,608
PREFERRED SHARES
Partial redemption of 8.29% Series K Cumulative Redeemable			0
Preferred Stock Preference Units Dividend Rate Percentage		8.29%
COMMON SHARES, $0.01 PAR VALUE
Conversion of OP Units into Common Shares				1	3,725			(3,726)
Exercise of share options				8	35,825
Employee Share Purchase Plan (ESPP)				1	3,685
Restricted shares				1	15,015
PAID IN CAPITAL
Conversion of OP Units into Common Shares				1	3,725			(3,726)
Exercise of share options				8	35,825
Employee Share Purchase Plan (ESPP)				1	3,685
Conversion of restricted shares to restricted units					0			0
Share-based employee compensation expense:
Restricted shares				1	15,015
Share options					3,432
ESPP discount					650
Common Shares repurchsed and retired					0
Offering costs					(314)
Supplemental Executive Retirement Plan (SERP)					748
Acquisition of Noncontrolling Interests – Partially Owned Properties					0				0
Change in market value of Redeemable Noncontrolling Interests – Operating Partnership	(115,093)				115,093
Adjustment for Noncontrolling Interests ownership in Operating Partnership					8,198			(8,198)
RETAINED EARNINGS
Net income attributable to controlling interests	4,292,163					4,292,163
Common Share distributions						(4,754,537)
Preferred Share distributions						(3,091)
Premium on redemption of Preferred Shares – cash charge						0
Accumulated other comprehensive income (loss) – derivative instruments:
Unrealized holding (losses) gains arising during the year	(3,915)						(3,915)
Losses reclassified into earnings from other comprehensive income	(41,758)						41,758
Accumulated other comprehensive income (loss) – foreign currency:
Currency translation adjustments arising during the year	264						264
OPERATING PARTNERSHIP
Issuance of restricted units to Noncontrolling Interests								1
Conversion of OP Units into Common Shares				1	3,725			(3,726)
Conversion of restricted shares to restricted units					0			0
Equity compensation associated with Noncontrolling Interests								18,180
Net income attributable to Noncontrolling Interests	4,480,104							171,511	16,430
Distributions to Noncontrolling Interests								(187,448)	(36,268)
Change in carrying value of Redeemable Noncontrolling Interests – Operating Partnership	(9,598)							9,598
Adjustment for Noncontrolling Interests ownership in Operating Partnership					8,198			(8,198)
PARTIALLY OWNED PROPERTIES
Net income attributable to Noncontrolling Interests	4,480,104							171,511	16,430
Contributions – Noncontrolling Interests – Partially Owned Properties	0								0
Distributions to Noncontrolling Interests								(187,448)	(36,268)
Acquisition of Noncontrolling Interests – Partially Owned Properties					0				0
Deconsolidation of previously consolidated Noncontrolling Interests									0
Other									25,839
Balance, end of year at Dec. 31, 2016	10,229,078		$ 37,280	$ 3,659	$ 8,758,422	$ 1,543,626	$ (113,909)
Balance, end of year at Dec. 31, 2016	$ 10,460,984							$ 221,297	$ 10,609