Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Statement of Cash Flows [Abstract]
Net income	$ 122,763	$ 12,154
Adjustments to reconcile net loss to net cash provided by operating activities:
Gain on sale of investment properties, including discontinued operations	69,911	8,350
Loss on extinguishment of debt	0	94
Impairment loss included in discontinued operations	0	12,721
Depreciation and amortization, including discontinued operations	45,950	41,148
Amortization of deferred financing costs	778	784
Amortization of stock options and restricted stock, net of forfeitures	1,421	1,422
Effect of certain non-cash adjustments to rental revenues	(5,605)	(3,056)
Income from unconsolidated joint ventures	(65,862)	(14,217)
Operating distributions from unconsolidated joint ventures	65,563	12,065
Land and multi-family cost of sales, net of closing costs paid	904	1,385
Payments to Acquire and Develop Land and Multi-Family Real Estate	0	51
Changes in other operating assets and liabilities:
Change in other receivables and other assets, net	(3,572)	(2,069)
Change in operating liabilities	6,247	(1,619)
Net cash provided by operating activities	98,676	52,411
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from investment property sales	171,779	73,052
Property acquisition, development and tenant asset expenditures	(1,502,016)	(94,118)
Investment in unconsolidated joint ventures	(2,139)	(6,571)
Distributions from unconsolidated joint ventures	86,752	25,767
Collection of notes receivable	1,233	1,156
Change in notes receivable and other assets	(1,930)	(2,733)
Change in restricted cash	(101)	2,180
Net cash provided by (used in) investing activities	(1,246,422)	(1,267)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facility	343,725	414,200
Repayment of credit facility	(292,650)	(518,950)
Proceeds from other notes payable	304,268	111,632
Repayment of notes payable	(76,314)	(27,694)
Payment of loan issuance costs	(1,693)	(3,419)
Proceeds from Issuance of Common Stock	826,529	0
Preferred Stock Redemption	(74,827)	0
Common dividends paid	(18,657)	(14,064)
Preferred dividends paid	(8,231)	(9,680)
Distributions to noncontrolling interests	(25,888)	(2,558)
Net cash provided by (used in) financing activities	976,262	(50,533)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(171,484)	611
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	176,892	4,858
CASH AND CASH EQUIVALENTS AT END OF PERIOD	5,408	5,469
INTEREST PAID, NET OF AMOUNTS CAPITALIZED	14,522	17,320
Transfer from operating properties to operating properties and related assets held for sale	49,435	174,054
Transfer from projects under development to operating properties	25,629	0
Transfer from other assets to projects under development	$ 3,062	$ 0