Consolidated Statements of Cash Flows (Unaudited) (USD $)	6 Months Ended
	Jul. 31, 2011		Jul. 31, 2010
Cash Flows from Operating Activities
Net earnings	$ 139,054,000		$ 128,989,000
Depreciation and amortization	111,245,000		117,366,000
Amortization of mortgage procurement costs	5,622,000		5,333,000
Impairment of real estate	5,070,000		1,100,000
Impairment of unconsolidated entities	0		15,181,000
Write-off of abandoned development projects	5,245,000		37,000
(Gain) loss on early extinguishment of debt	5,767,000		(8,193,000)
Net gain on disposition of partial interests in rental properties and other investment	(9,561,000)		(260,247,000)
Deferred income tax expense (benefit)	(3,392,000)		60,626,000
Equity in (earnings) loss of unconsolidated entities	(22,379,000)		2,939,000
Stock-based compensation expense	4,401,000		4,461,000
Amortization and mark-to-market adjustments of derivative instruments	574,000		10,501,000
Non-cash interest expense related to Puttable Equity-Linked Senior Notes	1,148,000		1,015,000
Cash distributions from operations of unconsolidated entities	23,763,000		17,951,000
Gain on disposition of rental properties	(121,695,000)		(6,204,000)
Cost of sales of land included in projects under construction and development and completed rental properties	2,059,000		11,059,000
Increase in land held for development or sale	(12,897,000)		(9,081,000)
(Increase) decrease in notes and accounts receivable	(4,109,000)		7,661,000
(Increase) decrease in other assets	(14,288,000)		5,290,000
Increase in restricted cash and escrowed funds used for operating purposes	(1,892,000)		(15,569,000)
Increase (decrease) in accounts payable and accrued expenses	3,285,000		(60,269,000)
Net cash provided by operating activities	134,533,000		65,948,000
Cash Flows from Investing Activities
Capital expenditures	(360,580,000)		(400,085,000)
Payment of lease procurement costs	(12,020,000)		(13,598,000)
Decrease (increase) in other assets	1,457,000		(22,026,000)
Decrease (increase) in restricted cash and escrowed funds used for investing purposes	137,016,000		(345,553,000)
Proceeds from dispositions of full or partial interests in rental properties	321,438,000		190,001,000
(Increase) decrease in investments in and advances to affiliates	(63,521,000)		11,078,000
Net cash provide by (used in) investing activities	23,790,000		(580,183,000)
Cash Flows from Financing Activities
Proceeds from nonrecourse mortgage debt and notes payable	176,364,000		330,555,000
Principal payments on nonrecourse mortgage debt and notes payable	(205,550,000)		(61,534,000)
Borrowings on bank revolving credit facility	464,575,000		477,822,000
Payments on bank revolving credit facility	(601,727,000)		(448,866,000)
Proceeds from issuance of Convertible Senior Notes, net of $10,625 of issuance costs	339,375,000
Payment of transaction costs related to Senior Notes exchanges for Class A common stock	(3,200,000)
Purchase of senior notes due 2011 and 2017			(16,569,000)
Payment of deferred financing costs	(9,859,000)		(19,793,000)
Change in restricted cash and escrowed funds and book overdrafts	(10,714,000)		(8,021,000)
Proceeds from issuance of Series A preferred stock, net of $5,544 of issuance costs			44,456,000
Payment for equity call hedge related to the issuance of Series A preferred stock			(17,556,000)
Dividends paid to preferred shareholders	(7,700,000)		(4,107,000)
Purchase of treasury stock	(1,630,000)		(711,000)
Exercise of stock options	177,000
Contributions from redeemable noncontrolling interest			181,909,000
Contributions from noncontrolling interests	2,909,000		2,499,000
Distributions to noncontrolling interests	(82,367,000)		(10,526,000)
Net cash provided by financing activities	60,653,000		449,558,000
Net increase (decrease) in cash and equivalents	218,976,000		(64,677,000)
Cash and equivalents at beginning of period	193,372,000		251,405,000
Cash and equivalents at end of period	412,348,000		186,728,000
Operating Activities
Increase in land held for development or sale	(7,401,000)	[1],[2],[3]	(10,182,000)	[2],[3]
Decrease in notes and accounts receivable	32,595,000	[4],[5]	17,981,000	[5],[6],[7]
Decrease in other assets	123,885,000	[4],[5],[8],[9]	71,595,000	[5],[6],[8]
Decrease (increase) in restricted cash and escrowed funds	149,790,000	[4],[5]	(1,106,000)	[5],[6]
Decrease in accounts payable and accrued expenses	(9,983,000)	[3],[4],[5],[8]	(110,145,000)	[3],[5],[6]
Total effect on operating activities	288,886,000		(31,857,000)
Investing Activities
Decrease in projects under construction and development	487,387,000	[10],[2],[3],[4]	21,494,000	[10],[2],[3],[6]
Decrease in completed rental properties	1,097,239,000	[2],[4],[5],[8]	560,548,000	[2],[5],[6],[8]
(Increase) decrease in investments in and advances to affiliates	(253,540,000)	[4],[5]	108,986,000	[11],[5],[6]
Total effect on investing activities	1,331,086,000		691,028,000
Financing Activities
Decrease in nonrecourse mortgage debt and notes payable	(1,569,240,000)	[1],[12],[4],[5],[8]	(654,188,000)	[11],[5],[6],[8]
Decrease in senior and subordinated debt	(40,000,000)	[9]	(167,658,000)	[13]
Increase in preferred stock			170,000,000	[13]
Increase in Class A common stock	959,000	[9]
Increase in additional paid-in capital	40,861,000	[10],[11],[12],[9]	2,243,000	[10],[13]
Increase in redeemable noncontrolling interest	1,987,000	[11]	40,000,000	[11]
Decrease in noncontrolling interest	(54,539,000)	[12],[4],[5]	(49,568,000)	[5],[6],[7]
Total effect on financing activities	(1,619,972,000)		(659,171,000)
Segment Discontinued Operations [Member]
Cash Flows from Operating Activities
Depreciation and amortization	2,216,000		5,877,000
Amortization of mortgage procurement costs	739,000		942,000
Impairment of real estate			45,410,000
Deferred income tax expense (benefit)	14,558,000		(16,227,000)
Gain on disposition of rental properties	$ (121,695,000)		$ (6,204,000)

[1] Assumption of debt in exchange for a 75% equity interest in a land development project in Dallas, Texas during the six months ended July 31, 2011.

[2] Commercial Group and Residential Group outlots reclassified prior to sale from projects under construction and development or completed rental properties to land held for sale

[3] Increase or decrease in construction payables included in accounts payable and accured expenses.

[4] Change to equity method of accounting from full consolidation for 8 Spruce Street and DKLB BKLN, apartments in the Residential Group, due to recapitalization transactions during the six months ended July 31, 2011.

[5] Disposition of partial interests in 15 New York retail properties and change to equity method of accounting for remaining ownership interest during the six months ended July 31, 2011 and disposition of partial interests in the Company's mixed-use University Park project in Cambridge, Masssachuetts and in The Grand, Lenox Club and Lenox Park apartment communities and change to equity method of accounting from full consolidation for the remaning ownership interest during six months ended July 31, 2010.

[6] Change in consolidation method of accounting for various entities in the Residential Group and Commercial Group during the six months ended July 31, 2010, due to the adoption of accounting guidance for the consolidation of variable interest entities.

[7] Receipt of a note receivable as a contribution from a noncontrolling interest during the six months ended July 31, 2010.

[8] Disposition of Waterfront Station East 4th & West 4th Buildings, office buildings and Charleston Marriott, a hotel, both in the Commercial Group, including assumption of nonrecourse mortgage debt by the buyers, during the six months ended July 31, 2011 and disposition of 101 San Fernando, an apartment community in the Residential Group, during the six months ended July 31, 2010

[9] Exchange of a portion of the Company's senior notes due 2016 for Class A common stock during the six months ended July 31, 2011 (see Note R- Capital Stock).

[10] Capitalization of stock-based compensation granted to employees directly involved with the acquisition, development and construction of real estate.

[11] Conversion of loans into investments in and advances to affiliates and redeemable noncontrolling interest in accordance with the amended operating agreement of Nets Sports and Entertainment, LLC, concurrent with the Company's closing on the purchase agreement with entities controlled by Mikhail Prokhorov during the six months ended July 31, 2010 and adjustments to redemption value of redeemable noncontrolling interest during the six months ended July 31, 2011.

[12] Difference between fair value of consideration transferred and the book value of noncontrolling interest in connection with the acquisition of certain partners' noncontrolling interests in Net Sports and Entertaintment, LLC and development projecs in the Commercial Group during the six months ended July 31, 2011.

[13] Exchange of a portion of the Company's senior notes due 2011, 2015 and 2017 for a new issue of 7.0% Series A Cumulative Perpetual Convertible Preferred Stock during the six months ended July 31, 2010 (see Note R - Capital Stock).