Investments in Partially Owned Entities (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Feb. 27, 2013
Partially Owned Property Balance Sheet Schedule
Properties	315		315
Apartment Units	79,458		79,458
ASSETS
Investment in real estate	$ 25,247,754,000		$ 25,247,754,000		$ 25,182,352,000
Accumulated depreciation	(5,119,342,000)		(5,119,342,000)		(4,905,406,000)
Investment in real estate, net	20,128,412,000		20,128,412,000		20,276,946,000
Cash and cash equivalents	497,843,000	$ 92,109,000	497,843,000	$ 92,109,000	42,276,000	$ 40,080,000
Investments in unconsolidated entities	65,952,000		65,952,000		68,101,000
Deposits – restricted	77,587,000		77,587,000		55,893,000
Other assets	398,417,000		398,417,000		428,899,000
Total assets	21,229,922,000		21,229,922,000		23,110,196,000
LIABILITIES AND EQUITY
Secured Debt	4,147,999,000		4,147,999,000		4,685,134,000
Accounts payable & accrued expenses	186,629,000		186,629,000		187,124,000
Accrued interest payable	58,175,000		58,175,000		85,221,000
Other Liabilities	333,551,000		333,551,000		366,387,000
Security deposits	64,242,000		64,242,000		77,582,000
Total liabilities	9,344,994,000		9,344,994,000		11,847,058,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	4,278,000		4,278,000		4,608,000
Total liabilities and equity	21,229,922,000		21,229,922,000		$ 23,110,196,000
Partially Owned Property Income Statement Schedule
Operating revenue	595,154,000	679,112,000	1,214,237,000	1,345,483,000
Property management	20,991,000	21,792,000	44,486,000	44,557,000
General and administrative/other	176,127,000	194,282,000	349,012,000	388,803,000
Depreciation	18,296,000	15,659,000	35,013,000	35,421,000
Operating income	206,018,000	246,255,000	422,643,000	464,586,000
Interest and other income	56,525,000	6,481,000	59,583,000	6,650,000
Interest:
Expense incurred, net	(86,472,000)	(110,866,000)	(299,964,000)	(219,648,000)
Amortization of deferred financing costs	(2,345,000)	(2,538,000)	(7,739,000)	(5,127,000)
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	172,222,000	137,562,000	170,463,000	244,761,000
Income and other tax (expense) benefit	(413,000)	(326,000)	(763,000)	(369,000)
(Loss) income from investments in unconsolidated entities	(800,000)	12,466,000	(1,904,000)	15,429,000
Net income	$ 228,400,000	$ 298,618,000	$ 3,960,231,000	$ 488,842,000
Consolidated VIE
Partially Owned Property Balance Sheet Schedule
Properties	18		18
Apartment Units	3,471		3,471
ASSETS
Investment in real estate	$ 667,414,000		$ 667,414,000
Accumulated depreciation	(214,810,000)		(214,810,000)
Investment in real estate, net	452,604,000		452,604,000
Cash and cash equivalents	17,860,000		17,860,000
Investments in unconsolidated entities	48,127,000		48,127,000
Deposits – restricted	353,000		353,000
Other assets	25,658,000		25,658,000
Total assets	544,602,000		544,602,000
LIABILITIES AND EQUITY
Secured Debt	318,114,000		318,114,000
Accounts payable & accrued expenses	1,966,000		1,966,000
Accrued interest payable	1,085,000		1,085,000
Other Liabilities	754,000		754,000
Security deposits	1,959,000		1,959,000
Total liabilities	323,878,000		323,878,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	4,278,000		4,278,000
Company equity/General and Limited Partners' Capital	216,446,000		216,446,000
Total equity/capital	220,724,000		220,724,000
Total liabilities and equity	$ 544,602,000		544,602,000
Partially Owned Property Income Statement Schedule
Operating revenue			46,331,000
Operating Expenses			11,319,000
Net operating income			35,012,000
Property management			1,633,000
General and administrative/other			10,755,000
Depreciation			40,000
Operating income			22,584,000
Interest and other income			37,000
Interest:
Expense incurred, net			(7,549,000)
Amortization of deferred financing costs			(218,000)
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			14,854,000
Income and other tax (expense) benefit			(44,000)
(Loss) income from investments in unconsolidated entities			(731,000)
Net income			$ 14,079,000
Unconsolidated Non-VIE
Partially Owned Property Balance Sheet Schedule
Properties	2		2
Apartment Units	945		945
ASSETS
Investment in real estate	$ 234,807,000		$ 234,807,000
Accumulated depreciation	(27,615,000)		(27,615,000)
Investment in real estate, net	207,192,000		207,192,000
Cash and cash equivalents	6,860,000		6,860,000
Investments in unconsolidated entities	0		0
Deposits – restricted	262,000		262,000
Other assets	448,000		448,000
Total assets	214,762,000		214,762,000
LIABILITIES AND EQUITY
Secured Debt	145,423,000		145,423,000
Accounts payable & accrued expenses	1,239,000		1,239,000
Accrued interest payable	691,000		691,000
Other Liabilities	312,000		312,000
Security deposits	488,000		488,000
Total liabilities	148,153,000		148,153,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	62,282,000		62,282,000
Company equity/General and Limited Partners' Capital	4,327,000		4,327,000
Total equity/capital	66,609,000		66,609,000
Total liabilities and equity	214,762,000		214,762,000
Partially Owned Property Income Statement Schedule
Operating revenue			13,139,000
Operating Expenses			4,348,000
Net operating income			8,791,000
Property management			383,000
General and administrative/other			5,246,000
Depreciation			1,000
Operating income			3,161,000
Interest and other income			0
Interest:
Expense incurred, net			(4,145,000)
Amortization of deferred financing costs			0
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			(984,000)
Income and other tax (expense) benefit			(13,000)
(Loss) income from investments in unconsolidated entities			0
Net income			(997,000)
Unconsolidated Non-VIE | Residual JV [Domain]
ASSETS
Investments in unconsolidated entities	$ (500,000)		$ (500,000)				$ 147,600,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired	60.00%		60.00%
Joint Venture Partner Ownership Percentage	40.00%		40.00%
Unconsolidated VIE
Partially Owned Property Balance Sheet Schedule
Properties	1		1
Apartment Units	336		336
ASSETS
Investment in real estate	$ 229,685,000		$ 229,685,000
Accumulated depreciation	(51,053,000)		(51,053,000)
Investment in real estate, net	178,632,000		178,632,000
Cash and cash equivalents	1,068,000		1,068,000
Investments in unconsolidated entities	0		0
Deposits – restricted	47,000		47,000
Other assets	913,000		913,000
Total assets	180,660,000		180,660,000
LIABILITIES AND EQUITY
Secured Debt	29,123,000		29,123,000
Accounts payable & accrued expenses	351,000		351,000
Accrued interest payable	0		0
Other Liabilities	541,000		541,000
Security deposits	155,000		155,000
Total liabilities	30,170,000		30,170,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	104,272,000		104,272,000
Company equity/General and Limited Partners' Capital	46,218,000		46,218,000
Total equity/capital	150,490,000		150,490,000
Total liabilities and equity	$ 180,660,000		180,660,000
Partially Owned Property Income Statement Schedule
Operating revenue			5,794,000
Operating Expenses			2,337,000
Net operating income			3,457,000
Property management			38,000
General and administrative/other			3,716,000
Depreciation			165,000
Operating income			(462,000)
Interest and other income			0
Interest:
Expense incurred, net			(545,000)
Amortization of deferred financing costs			0
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			(1,007,000)
Income and other tax (expense) benefit			0
(Loss) income from investments in unconsolidated entities			0
Net income			$ (1,007,000)
Partially Owned Properties – Unconsolidated
Partially Owned Property Balance Sheet Schedule
Properties	3		3
Apartment Units	1,281		1,281
ASSETS
Investment in real estate	$ 464,492,000		$ 464,492,000
Accumulated depreciation	(78,668,000)		(78,668,000)
Investment in real estate, net	385,824,000		385,824,000
Cash and cash equivalents	7,928,000		7,928,000
Investments in unconsolidated entities	0		0
Deposits – restricted	309,000		309,000
Other assets	1,361,000		1,361,000
Total assets	395,422,000		395,422,000
LIABILITIES AND EQUITY
Secured Debt	174,546,000		174,546,000
Accounts payable & accrued expenses	1,590,000		1,590,000
Accrued interest payable	691,000		691,000
Other Liabilities	853,000		853,000
Security deposits	643,000		643,000
Total liabilities	178,323,000		178,323,000
Noncontrolling Interests – Partially Owned Properties/Partners' equity	166,554,000		166,554,000
Company equity/General and Limited Partners' Capital	50,545,000		50,545,000
Total equity/capital	217,099,000		217,099,000
Total liabilities and equity	$ 395,422,000		395,422,000
Partially Owned Property Income Statement Schedule
Operating revenue			18,933,000
Operating Expenses			6,685,000
Net operating income			12,248,000
Property management			421,000
General and administrative/other			8,962,000
Depreciation			166,000
Operating income			2,699,000
Interest and other income			0
Interest:
Expense incurred, net			(4,690,000)
Amortization of deferred financing costs			0
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			(1,991,000)
Income and other tax (expense) benefit			(13,000)
(Loss) income from investments in unconsolidated entities			0
Net income			$ (2,004,000)