Segment Information (Details 1) (USD $)	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010
Reconciliation of EBDT to Net Earnings (Loss) by Segment
EBDT	$ 70,706,000	$ 105,560,000	$ 198,082,000	$ 176,027,000
Depreciation and amortization - Real Estate Groups	(54,538,000)	(58,040,000)	(111,245,000)	(117,366,000)
Amortization of mortgage procurement costs	(2,727,000)	(2,721,000)	(5,622,000)	(5,333,000)
Straight-line rent adjustment	(2,714,000)	5,513,000	(844,000)	8,714,000
Preference payment	(586,000)	(586,000)	(1,171,000)	(1,171,000)
Net gain on disposition of partial interests in rental properties and other investment	0	259,381,000	9,561,000	260,247,000
Gain on disposition of partial interests in rental properties, net of tax		125,168,000		125,346,000
Gain on disposition of unconsolidated entities			12,567,000
Loss on disposition of unconsolidated entities, net of tax		(536,000)		(507,000)
Impairment of real estate	(235,000)	(1,100,000)	(5,070,000)	(1,100,000)
Impairment of real estate, net of tax		(28,472,000)		(28,472,000)
Impairment of unconsolidated entities, net of tax		(1,398,000)		(9,294,000)
Impairment of consolidated and unconsolidated entities			(5,070,000)
Discontinued operations:
Straight-line rent adjustment	217,000		571,000
Straight-line rent adjustment, net of tax		(971,000)		(1,134,000)
Gain on disposition of rental properties	29,899,000		39,937,000
Income tax expense:
Deferred income taxes	4,492,000	(76,088,000)	3,392,000	(60,626,000)
Current income taxes attributable to above dispositions	1,679,000	(5,478,000)	(15,134,000)	(11,570,000)
Net earnings attributable to Forest City Enterprises, Inc.	8,134,000	122,846,000	55,701,000	107,284,000
Preferred dividends	(3,850,000)	(4,107,000)	(7,700,000)	(4,107,000)
Net earnings attributable to Forest City Enterprises, Inc. common shareholders	4,284,000	118,739,000	48,001,000	103,177,000
Commercial Group [Member]
Reconciliation of EBDT to Net Earnings (Loss) by Segment
EBDT	77,497,000	72,020,000	192,776,000	133,101,000
Depreciation and amortization - Real Estate Groups	(40,380,000)	(44,847,000)	(83,229,000)	(91,250,000)
Straight-line rent adjustment	(3,002,000)	5,201,000	(969,000)	7,946,000
Preference payment	(586,000)	(586,000)	(1,171,000)	(1,171,000)
Net gain on disposition of partial interests in rental properties and other investment			9,561,000
Gain on disposition of partial interests in rental properties, net of tax		125,047,000		107,615,000
Loss on disposition of unconsolidated entities, net of tax		(536,000)		(507,000)
Impairment of real estate, net of tax		(27,800,000)		(27,800,000)
Impairment of unconsolidated entities, net of tax				(7,441,000)
Impairment of consolidated and unconsolidated entities			(3,435,000)
Discontinued operations:
Straight-line rent adjustment	217,000		571,000
Straight-line rent adjustment, net of tax		(971,000)		(1,134,000)
Gain on disposition of rental properties	29,899,000		39,937,000
Income tax expense:
Net earnings attributable to Forest City Enterprises, Inc.	51,907,000	107,709,000	131,991,000	88,593,000
Net earnings attributable to Forest City Enterprises, Inc. common shareholders	51,907,000	107,709,000	131,991,000	88,593,000
Commercial Group [Member] | Real Estate Groups [Member]
Reconciliation of EBDT to Net Earnings (Loss) by Segment
Depreciation and amortization - Real Estate Groups	(49,436,000)	(48,307,000)	(99,074,000)	(98,260,000)
Amortization of mortgage procurement costs	(2,360,000)	(2,062,000)	(4,842,000)	(4,447,000)
Discontinued operations:
Depreciation and amortization - Real Estate Groups	(238,000)		(1,030,000)
Depreciation and amortization - Real Estate Groups, net of tax		(2,991,000)		(5,208,000)
Amortization of mortgage procurement costs - Real Estate Groups	(84,000)		(333,000)
Amortization of mortgage procurement costs - Real Estate Groups, net of tax		(881,000)		(928,000)
Deferred taxes - Real Estate Groups		17,383,000		17,406,000
Income tax expense:
Deferred income taxes		(27,808,000)		(30,579,000)
Residential Group [Member]
Reconciliation of EBDT to Net Earnings (Loss) by Segment
EBDT	19,906,000	25,166,000	46,757,000	52,779,000
Depreciation and amortization - Real Estate Groups	(13,748,000)	(12,654,000)	(27,193,000)	(25,032,000)
Straight-line rent adjustment	288,000	319,000	125,000	772,000
Gain on disposition of partial interests in rental properties, net of tax		121,000		17,731,000
Gain on disposition of unconsolidated entities			12,567,000
Impairment of real estate	(235,000)
Impairment of consolidated and unconsolidated entities			(235,000)
Discontinued operations:
Gain on disposition of rental properties, net of tax		1,099,000		1,099,000
Income tax expense:
Net earnings attributable to Forest City Enterprises, Inc.	(115,000)	7,418,000	19,987,000	28,091,000
Net earnings attributable to Forest City Enterprises, Inc. common shareholders	(115,000)	7,418,000	19,987,000	28,091,000
Residential Group [Member] | Real Estate Groups [Member]
Reconciliation of EBDT to Net Earnings (Loss) by Segment
Depreciation and amortization - Real Estate Groups	(19,188,000)	(18,162,000)	(37,501,000)	(35,485,000)
Amortization of mortgage procurement costs	(886,000)	(601,000)	(1,726,000)	(1,143,000)
Discontinued operations:
Depreciation and amortization - Real Estate Groups, net of tax		(254,000)		(636,000)
Amortization of mortgage procurement costs - Real Estate Groups, net of tax		(5,000)		(13,000)
Deferred taxes - Real Estate Groups		(291,000)		(400,000)
Income tax expense:
Deferred income taxes		26,000		(6,613,000)
Land Development Group [Member]
Reconciliation of EBDT to Net Earnings (Loss) by Segment
EBDT	(214,000)	2,858,000	892,000	566,000
Depreciation and amortization - Real Estate Groups	(54,000)	(100,000)	(114,000)	(199,000)
Straight-line rent adjustment		(7,000)		(4,000)
Impairment of real estate, net of tax		(672,000)		(672,000)
Impairment of unconsolidated entities, net of tax		(1,398,000)		(1,853,000)
Impairment of consolidated and unconsolidated entities			(1,400,000)
Income tax expense:
Net earnings attributable to Forest City Enterprises, Inc.	(366,000)	(479,000)	(807,000)	(2,501,000)
Net earnings attributable to Forest City Enterprises, Inc. common shareholders	(366,000)	(479,000)	(807,000)	(2,501,000)
Land Development Group [Member] | Real Estate Groups [Member]
Reconciliation of EBDT to Net Earnings (Loss) by Segment
Depreciation and amortization - Real Estate Groups	(67,000)	(75,000)	(153,000)	(154,000)
Amortization of mortgage procurement costs	(85,000)	(84,000)	(146,000)	(164,000)
Income tax expense:
Deferred income taxes		(1,101,000)		(220,000)
The Nets [Member]
Reconciliation of EBDT to Net Earnings (Loss) by Segment
EBDT	(3,382,000)	14,745,000	(3,686,000)	11,372,000
Depreciation and amortization - Real Estate Groups
Income tax expense:
Net earnings attributable to Forest City Enterprises, Inc.	(3,382,000)	14,745,000	(3,686,000)	11,372,000
Net earnings attributable to Forest City Enterprises, Inc. common shareholders	(3,382,000)	14,745,000	(3,686,000)	11,372,000
Corporate Activities [Member]
Reconciliation of EBDT to Net Earnings (Loss) by Segment
EBDT	(23,101,000)	(9,229,000)	(38,657,000)	(21,791,000)
Depreciation and amortization - Real Estate Groups	(356,000)	(439,000)	(709,000)	(885,000)
Income tax expense:
Deferred income taxes	(6,353,000)		(11,166,000)
Current income taxes attributable to above dispositions	(10,456,000)		(41,961,000)
Net earnings attributable to Forest City Enterprises, Inc.	(39,910,000)	(6,547,000)	(91,784,000)	(18,271,000)
Preferred dividends	(3,850,000)	(4,107,000)	(7,700,000)	(4,107,000)
Net earnings attributable to Forest City Enterprises, Inc. common shareholders	(43,760,000)	(10,654,000)	(99,484,000)	(22,378,000)
Corporate Activities [Member] | Real Estate Groups [Member]
Income tax expense:
Deferred income taxes		2,682,000		3,520,000
Real Estate Groups [Member]
Reconciliation of EBDT to Net Earnings (Loss) by Segment
Depreciation and amortization - Real Estate Groups	(68,691,000)	(66,544,000)	(136,728,000)	(133,899,000)
Amortization of mortgage procurement costs	(3,331,000)	(2,747,000)	(6,714,000)	(5,754,000)
Discontinued operations:
Depreciation and amortization - Real Estate Groups	(238,000)		(1,030,000)
Depreciation and amortization - Real Estate Groups, net of tax		(3,245,000)		(5,844,000)
Amortization of mortgage procurement costs - Real Estate Groups	(84,000)		(333,000)
Amortization of mortgage procurement costs - Real Estate Groups, net of tax		(886,000)		(941,000)
Deferred taxes - Real Estate Groups		17,092,000		17,006,000
Gain on disposition of rental properties, net of tax		1,099,000		1,099,000
Income tax expense:
Deferred income taxes	(6,353,000)	(26,201,000)	(11,166,000)	(33,892,000)
Current income taxes attributable to above dispositions	$ (10,456,000)		$ (41,961,000)