Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reconciliation of NOI to net income
Net income		$ 172,253	$ 172,197	$ 380,306	$ 313,796
Indirect operating expenses, net of corporate income		14,817	12,343	30,215	23,161
Investments and investment management expense		1,073	1,137	2,107	2,116
Expensed acquisition, development and other pursuit costs		673	2,017	1,860	2,732
Gains (Losses) on Extinguishment of Debt		(7,749)	412	(7,749)	412
Interest expense, net	[1]	44,590	43,722	90,164	86,255
General and administrative expense		11,628	10,220	22,111	19,456
Equity in (income) loss of unconsolidated real estate entities		(13,806)	(7,710)	(48,371)	(12,933)
Depreciation expense	[1]	118,627	110,395	235,480	216,762
Casualty and Impairment (Gain) Loss		(17,114)	0	(11,326)	0
Gain on sale of real estate assets		(9,625)	(60,945)	(80,583)	(60,945)
Gain on sale of discontinued operations		0	0	0	(37,869)
Income from discontinued operations		0	0	0	(310)
Net operating income from real estate assets sold or held for sale, not classified as discontinued operations		(1,353)	(6,240)	(2,791)	(12,522)
Net operating income		314,014	277,548	611,423	540,111
Continuing Operations
Reconciliation of NOI to net income
Net operating income		$ 314,014	$ 277,548	$ 611,423	$ 540,111

[1] Includes amounts associated with assets sold or held for sale, not classified as discontinued operations.