Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Percentage of physical occupancy									95.00%
Anniversary of Completion of Development or Redevelopment (in years)									1 year
Reconciliation of NOI to net income
Net income	$ 155,352	$ 206,076	$ 172,253	$ 208,053	$ 142,530	$ 241,001	$ 172,197	$ 141,599	$ 741,733	$ 697,327	$ 352,771
Indirect operating expenses, net of corporate income									56,973	49,055	41,554
Investments and investment management expense									4,370	4,485	3,990
Expensed acquisition, development and other pursuit costs, net of recoveries									6,822	(3,717)	45,050
Interest expense, net									175,615	180,618	172,402
(Gain) loss on extinguishment of debt, net									(26,736)	412	14,921
Loss on interest rate contract									0	0	51,000
General and administrative expense									42,396	41,425	39,573
Equity in (income) loss of unconsolidated entities									(70,018)	(148,766)	11,154
Depreciation expense									477,923	442,682	560,215
Income tax expense									1,861	9,368	0
Casualty (gain) loss and impairment loss, net									(10,542)	0	0
Gain on sale of real estate assets									(125,272)	(85,415)	(240)
Gain on sale of discontinued operations									0	(37,869)	(278,231)
Income from discontinued operations									0	(310)	(16,713)
Net operating income from real estate assets sold or held for sale, not classified as discontinued operations									(10,920)	(27,357)	(31,388)
Net operating income									$ 1,264,205	$ 1,121,938	$ 966,058