Investments in Partially Owned Entities (Details) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Feb. 27, 2013
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	317
Number of Units in Real Estate Property	83,992
ASSETS
Investment in real estate	$ 25,120,866,000		$ 25,182,352,000
Accumulated depreciation	(4,977,274,000)		(4,905,406,000)
Investment in real estate, net	20,143,592,000		20,276,946,000
Cash and cash equivalents	368,049,000	$ 49,418,000	42,276,000	$ 40,080,000
Investments in unconsolidated entities	66,476,000		68,101,000
Deposits – restricted	241,741,000		55,893,000
Other assets	422,079,000		428,899,000
Total assets	21,301,292,000		23,110,196,000
LIABILITIES AND EQUITY
Secured Debt	4,223,681,000		4,685,134,000
Accounts payable & accrued expenses	215,817,000		187,124,000
Accrued interest payable	69,404,000		85,221,000
Other Liabilities	347,553,000		366,387,000
Security deposits	63,592,000		77,582,000
Total liabilities	9,471,497,000		11,847,058,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	4,399,000		4,608,000
Liabilities and Equity	21,301,292,000		$ 23,110,196,000
Partially Owned Property Income Statement Schedule
Operating revenue	619,083,000	666,371,000
Property management	23,495,000	22,765,000
General and administrative/other	172,885,000	194,521,000
Depreciation	16,717,000	19,762,000
Operating income	216,625,000	218,331,000
Interest and other income	3,058,000	169,000
Interest:
Expense incurred, net	(213,492,000)	(108,782,000)
Amortization of deferred financing costs	(5,394,000)	(2,589,000)
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(1,759,000)	107,199,000
Income and other tax (expense) benefit	(350,000)	(43,000)
(Loss) income from investments in unconsolidated entities	(1,104,000)	2,963,000
Net income	$ 3,731,831,000	$ 190,224,000
Consolidated VIE
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	18
Number of Units in Real Estate Property	3,471
ASSETS
Investment in real estate	$ 665,996,000
Accumulated depreciation	(209,424,000)
Investment in real estate, net	456,572,000
Cash and cash equivalents	15,051,000
Investments in unconsolidated entities	48,797,000
Deposits – restricted	351,000
Other assets	25,948,000
Total assets	546,719,000
LIABILITIES AND EQUITY
Secured Debt	317,801,000
Accounts payable & accrued expenses	2,786,000
Accrued interest payable	1,099,000
Other Liabilities	521,000
Security deposits	1,939,000
Total liabilities	324,146,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	4,399,000
Company equity/General and Limited Partners' Capital	218,174,000
Total equity/capital	222,573,000
Liabilities and Equity	546,719,000
Partially Owned Property Income Statement Schedule
Operating revenue	22,997,000
Operating Expenses	5,598,000
Net operating income	17,399,000
Property management	811,000
General and administrative/other	15,000
Depreciation	5,369,000
Operating income	11,204,000
Interest and other income	20,000
Interest:
Expense incurred, net	(4,038,000)
Amortization of deferred financing costs	(147,000)
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	7,039,000
Income and other tax (expense) benefit	(12,000)
(Loss) income from investments in unconsolidated entities	(369,000)
Net income	$ 6,658,000
Unconsolidated Non-VIE
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	2
Number of Units in Real Estate Property	945
ASSETS
Investment in real estate	$ 234,383,000
Accumulated depreciation	(24,991,000)
Investment in real estate, net	209,392,000
Cash and cash equivalents	7,836,000
Investments in unconsolidated entities	0
Deposits – restricted	242,000
Other assets	103,000
Total assets	217,573,000
LIABILITIES AND EQUITY
Secured Debt	145,423,000
Accounts payable & accrued expenses	1,729,000
Accrued interest payable	691,000
Other Liabilities	258,000
Security deposits	510,000
Total liabilities	148,611,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	63,809,000
Company equity/General and Limited Partners' Capital	5,153,000
Total equity/capital	68,962,000
Liabilities and Equity	217,573,000
Partially Owned Property Income Statement Schedule
Operating revenue	6,528,000
Operating Expenses	2,196,000
Net operating income	4,332,000
Property management	190,000
General and administrative/other	0
Depreciation	2,621,000
Operating income	1,521,000
Interest and other income	0
Interest:
Expense incurred, net	(2,072,000)
Amortization of deferred financing costs	0
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(551,000)
Income and other tax (expense) benefit	0
(Loss) income from investments in unconsolidated entities	0
Net income	(551,000)
Unconsolidated Non-VIE | Residual JV [Domain]
ASSETS
Investments in unconsolidated entities	$ (900,000)				$ 147,600,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired	60.00%
Joint Venture Partner Ownership Percentage	40.00%
Unconsolidated VIE
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	1
Number of Units in Real Estate Property	336
ASSETS
Investment in real estate	$ 229,599,000
Accumulated depreciation	(49,194,000)
Investment in real estate, net	180,405,000
Cash and cash equivalents	1,201,000
Investments in unconsolidated entities	0
Deposits – restricted	47,000
Other assets	786,000
Total assets	182,439,000
LIABILITIES AND EQUITY
Secured Debt	29,269,000
Accounts payable & accrued expenses	351,000
Accrued interest payable	0
Other Liabilities	216,000
Security deposits	159,000
Total liabilities	29,995,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	108,968,000
Company equity/General and Limited Partners' Capital	43,476,000
Total equity/capital	152,444,000
Liabilities and Equity	182,439,000
Partially Owned Property Income Statement Schedule
Operating revenue	2,913,000
Operating Expenses	1,153,000
Net operating income	1,760,000
Property management	19,000
General and administrative/other	86,000
Depreciation	1,858,000
Operating income	(203,000)
Interest and other income	0
Interest:
Expense incurred, net	(272,000)
Amortization of deferred financing costs	0
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(475,000)
Income and other tax (expense) benefit	0
(Loss) income from investments in unconsolidated entities	0
Net income	$ (475,000)
Unconsolidated Properties [Member]
Partially Owned Property Balance Sheet Schedule
Number of Real Estate Properties	3
Number of Units in Real Estate Property	1,281
ASSETS
Investment in real estate	$ 463,982,000
Accumulated depreciation	(74,185,000)
Investment in real estate, net	389,797,000
Cash and cash equivalents	9,037,000
Investments in unconsolidated entities	0
Deposits – restricted	289,000
Other assets	889,000
Total assets	400,012,000
LIABILITIES AND EQUITY
Secured Debt	174,692,000
Accounts payable & accrued expenses	2,080,000
Accrued interest payable	691,000
Other Liabilities	474,000
Security deposits	669,000
Total liabilities	178,606,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	172,777,000
Company equity/General and Limited Partners' Capital	48,629,000
Total equity/capital	221,406,000
Liabilities and Equity	400,012,000
Partially Owned Property Income Statement Schedule
Operating revenue	9,441,000
Operating Expenses	3,349,000
Net operating income	6,092,000
Property management	209,000
General and administrative/other	86,000
Depreciation	4,479,000
Operating income	1,318,000
Interest and other income	0
Interest:
Expense incurred, net	(2,344,000)
Amortization of deferred financing costs	0
(Loss) income before income and other taxes, (loss) income from investments in unconsolidated entities, net gain (loss) on sales of real estate properties and land parcels and discontinued operations	(1,026,000)
Income and other tax (expense) benefit	0
(Loss) income from investments in unconsolidated entities	0
Net income	$ (1,026,000)