Forest City Realty Trust (FCE-A) 10-K 22 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 16, 2018	Jun. 30, 2016
Document Information [Line Items]
Entity Registrant Name	FOREST CITY REALTY TRUST, INC.
Entity Central Index Key	1,647,509
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 5,864,717,541
Entity Common Stock, Shares Outstanding		266,733,073

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Real Estate
Completed rental properties	$ 7,154,607,000	$ 7,112,347,000
Projects under construction and development	568,552,000	734,980,000
Land inventory	57,296,000	68,238,000
Total Real Estate	7,780,455,000	7,915,565,000
Less accumulated depreciation	(1,484,163,000)	(1,442,006,000)
Real Estate, net – (variable interest entities $2,383.2 million and $2,270.3 million, respectively)	6,296,292,000	6,473,559,000
Cash and equivalents – (variable interest entities $55.3 million and $59.3 million, respectively)	204,260,000	174,619,000
Restricted cash – (variable interest entities $65.5 million and $46.5 million, respectively)	146,131,000	149,300,000
Accounts receivable, net - (variable interest entities $32.2 million and $72.2 million, respectively)	225,022,000	208,563,000
Notes receivable - (variable interest entities $132.8 million and $154.3 million, respectively)	398,785,000	383,163,000
Investments in and advances to unconsolidated entities	550,362,000	564,779,000
Other assets – (variable interest entities $66.6 million and $72.2 million, respectively)	242,435,000	274,614,000
Total Assets	8,063,287,000	8,228,597,000
Liabilities
Nonrecourse mortgage debt and notes payable, net – (variable interest entities $1,448.2 million and $1,437.8 million, respectively)	2,998,361,000	3,120,833,000
Revolving credit facility	0	0
Term loan facility, net	333,668,000	333,268,000
Convertible senior debt, net	112,637,000	112,181,000
Accounts payable, accrued expenses and other liabilities – (variable interest entities $259.9 million and $241.9 million, respectively)	650,022,000	726,724,000
Cash distributions and losses in excess of investments in unconsolidated entities	123,882,000	150,592,000
Total Liabilities	4,218,570,000	4,443,598,000
Commitments and Contingencies	0	0
Stockholders’ Equity
Preferred stock – $.01 par value; 20,000,000 shares authorized, no shares issued	0	0
Common stock – $.01 par value
Common stock, value	2,653,000	2,587,000
Additional paid-in capital	2,537,538,000	2,483,275,000
Retained earnings	896,806,000	812,386,000
Accumulated other comprehensive loss	(8,563,000)	(14,410,000)
Total Stockholders’ Equity	3,428,434,000	3,283,838,000
Noncontrolling interest	416,283,000	501,161,000
Total Equity	3,844,717,000	3,784,999,000
Total Liabilities and Equity	8,063,287,000	8,228,597,000
Common Stock Class A
Common stock – $.01 par value
Common stock, value	2,653,000	2,399,000
Total Equity	2,653,000	2,399,000
Common Stock Class B
Common stock – $.01 par value
Common stock, value	0	188,000
Total Equity	$ 0	$ 188,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Real Estate, net	$ 6,296,292	$ 6,473,559
Cash and equivalents	204,260	174,619
Restricted cash	146,131	149,300
Accounts receivable, net	225,022	208,563
Notes receivable	398,785	383,163
Other assets	242,435	274,614
Nonrecourse mortgage debt and notes payable, net	2,998,361	3,120,833
Accounts payable, accrued expenses and other liabilities	$ 650,022	$ 726,724
Preferred stock, without par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	0	0
Common stock, par value per share	$ 0.010
Variable interest entities
Real Estate, net	$ 2,383,200	$ 2,270,300
Cash and equivalents	55,300	59,300
Restricted cash	65,500	46,500
Accounts receivable, net	32,200	72,200
Notes receivable	132,800	154,300
Other assets	66,600	72,200
Nonrecourse mortgage debt and notes payable, net	1,448,200	1,437,800
Accounts payable, accrued expenses and other liabilities	$ 259,900	$ 241,900
Common Stock Class A
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	371,000,000	371,000,000
Common stock, shares issued	265,343,283	239,937,796
Common stock, shares outstanding	265,343,283	239,937,796
Common Stock Class B
Common stock, par value per share	$ 0	$ 0.01
Common stock, shares authorized	0	56,000,000
Common stock, shares issued	0	18,788,169
Common stock, shares outstanding	0	18,788,169

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues [Abstract]
Rental	$ 665,354,000	$ 649,923,000	$ 625,725,000
Tenant recoveries	106,703,000	117,144,000	133,829,000
Service and management fees	37,220,000	53,824,000	45,263,000
Parking and other	42,871,000	56,996,000	62,376,000
Land sales	59,778,000	48,078,000	79,169,000
Military Housing	0	3,518,000	31,869,000
Total revenues	911,926,000	929,483,000	978,231,000
Expenses
Property operating and management	297,143,000	337,951,000	383,088,000
Real estate taxes	85,662,000	90,468,000	91,274,000
Ground rent	15,235,000	14,375,000	11,348,000
Cost of land sales	27,708,000	13,661,000	31,413,000
Military Housing operating	0	2,730,000	8,130,000
Corporate general and administrative	62,149,000	62,683,000	51,974,000
Organizational transformation and termination benefits	34,395,000	31,708,000	48,125,000
Total operating expenses	522,292,000	553,576,000	625,352,000
Depreciation and amortization	248,353,000	250,848,000	252,925,000
Write-offs of abandoned development projects and demolition costs	1,596,000	10,348,000	9,534,000
Impairment of real estate	44,288,000	156,825,000	451,434,000
Total Expenses	816,529,000	971,597,000	1,339,245,000
Operating income (loss)	95,397,000	(42,114,000)	(361,014,000)
Interest and other income	53,651,000	46,229,000	37,739,000
Gain on change in control of interests	0	0	486,279,000
Interest expense	(120,431,000)	(131,441,000)	(157,166,000)
Reclassification adjustment for interest rate swap breakage fee	0	(24,635,000)	0
Amortization of mortgage procurement costs	(5,550,000)	(5,719,000)	(7,549,000)
Loss on extinguishment of debt	(2,961,000)	(32,960,000)	(65,086,000)
Earnings (loss) before income taxes and earnings from unconsolidated entities	20,106,000	(190,640,000)	(66,797,000)
Earnings (loss) from unconsolidated entities
Equity in earnings	25,163,000	29,701,000	22,313,000
Net gain on disposition of interest in unconsolidated entities	110,221,000	13,166,000	20,293,000
Impairment	(10,600,000)	(306,400,000)	(13,844,000)
Earnings (loss) from unconsolidated entities, gross of tax	124,784,000	(263,533,000)	28,762,000
Loss before income taxes	144,890,000	(454,173,000)	(38,035,000)
Income tax expense (benefit) of taxable REIT subsidiaries (2016)
Current	6,586,000	3,240,000	2,139,000
Deferred	(28,200,000)	493,000	(583,917,000)
Total income tax expense (benefit)	(21,614,000)	3,733,000	(581,778,000)
Earnings (loss) before gains (loss) on disposal of real estate	166,504,000	(457,906,000)	543,743,000
Net gain (loss) on disposition of full or partial interest in development projects, net of tax	(113,000)	136,117,000	0
Net gain on disposition of full or partial interest in rental properties, net of tax	18,800,000	121,284,000	1,067,000
Gain on disposition of rental property in deed-in-lieu transaction	29,845,000	0	0
Earnings (loss) from continuing operations	215,036,000	(200,505,000)	544,810,000
Discontinued operations, net of tax:
Operating loss from rental properties	0	(1,126,000)	(27,520,000)
Gain on disposition	0	49,353,000	0
Equity in earnings (loss)	0	(822,000)	(24,952,000)
Earnings (loss) form discontinued operations	0	47,405,000	(52,472,000)
Net earnings (loss)	215,036,000	(153,100,000)	492,338,000
Noncontrolling interests, gross of tax
Earnings from continuing operations attributable to noncontrolling interests	(9,006,000)	(6,078,000)	(13,258,000)
Loss from discontinued operations attributable to noncontrolling interests	0	776,000	16,962,000
(Earnings) loss attributable to noncontrolling interest	(9,006,000)	(5,302,000)	3,704,000
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	$ 206,030,000	$ (158,402,000)	$ 496,042,000
Basic earnings (loss) per common share
Earnings (loss) from continuing operations attributable to common stockholders	$ 0.78	$ (0.80)	$ 2.19
Earnings (loss) from discontinued operations attributable to common stockholders	0	0.19	(0.14)
Net earnings (loss) attributable to common stockholders	0.78	(0.61)	2.05
Diluted earnings (loss) per common share
Earnings (loss) from continuing operations attributable to common shareholders	0.78	(0.80)	2.10
Earnings (loss) from discontinued operations attributable to common stockholders	0	0.19	(0.13)
Net earnings (loss) attributable to common stockholders	$ 0.78	$ (0.61)	$ 1.97

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net earnings (loss)	$ 215,036,000	$ (153,100,000)	$ 492,338,000
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments (net of tax of $0, $0 and $(18), respectively)	0	95,000	24,000
Unrealized net gain on interest rate derivative contracts (net of tax of $0, $0 and $(5,612), respectively)	5,861,000	28,780,000	22,584,000
Realized loss on interest rate swap breakage fee	0	24,635,000	0
One-time adjustment to deferred taxes on OCI related to REIT conversion	0	0	(31,651,000)
Total other comprehensive income (loss), net of tax	5,861,000	53,510,000	(9,043,000)
Comprehensive income (loss)	220,897,000	(99,590,000)	483,295,000
Comprehensive (income) loss attributable to noncontrolling interest	(9,020,000)	(5,317,000)	3,688,000
Total comprehensive income (loss) attributable to Forest City Realty Trust, Inc.	$ 211,877,000	$ (104,907,000)	$ 486,983,000

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Tax amount related to foreign currency translation adjustments	$ 0	$ 0	$ (18,000)
Tax amount related to unrealized net gains (losses) on interest rate derivative contracts	$ 0	$ 0	$ (5,612,000)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($)	Total	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interest	Common Stock Class A	Common Stock Class B
Balance, Shares at Dec. 31, 2014				1,095,000			180,859,000	19,209,000
Balance at Dec. 31, 2014	$ 2,152,723,000	$ 1,165,828,000	$ 563,198,000	$ (18,922,000)	$ (58,846,000)	$ 434,776,000	$ 60,286,000	$ 6,403,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss), net of amounts attributable to redeemable noncontrolling interest	509,300,000		496,042,000			13,258,000
Other comprehensive income (loss), net of tax	(9,043,000)				(9,059,000)	16,000
Issuance of Class A shares in equity offering, shares							37,375,000
Issuance of Class A shares in equity offering	806,500,000	794,042,000					$ 12,458,000
Adjustment of Class A and Class B par value from $.33 to $.01	$ 0	83,332,000					$ (77,252,000)	$ (6,080,000)
Purchase of treasury stock, Shares	222,537			223,000
Purchase of treasury stock	$ (5,543,000)			$ (5,543,000)
Conversion of Class B to Class A Shares, shares							404,000	(404,000)
Conversion of Class B to Class A shares	0						$ 135,000	$ (135,000)
Proceeds and Class A shares received from termination of Convertible Senior Notes hedge, shares				258,000
Proceeds and Class A shares received from termination of Convertible Senior Notes hedge	17,818,000	24,321,000		$ (6,503,000)
Issuance of Class A shares in exchange for Convertible Senior Notes, shares							19,967,000
Issuance of Class A shares in exchange for Convertible Senior Notes	410,580,000	403,924,000					$ 6,656,000
Restricted stock and performance shares vested, shares							810,000
Restricted stock and performance shares vested	0	(253,000)					$ 253,000
Repurchase of Class A common shares, shares							(26,000)
Repurchase of Class A common shares	(579,000)	(579,000)
Exercise of stock options and write-off of deferred tax asset related to expired stock options, shares				(104,000)
Exercise of stock options and write-off of deferred tax asset related to expired stock options	(48,000)	(2,079,000)		$ 2,031,000
Stock-based compensation	31,835,000	31,835,000
Exchange of 2006 Class A Common Units for Class A shares, shares							1,032,000
Exchange of 2006 Class A Common Units for Class A shares	0	52,319,000				(52,663,000)	$ 344,000
Acquisition of partner's noncontrolling interest in consolidated subsidiaries	(312,000)	(303,000)				(9,000)
Contributions from noncontrolling interests	106,244,000					106,244,000
Distributions to noncontrolling interests	(44,624,000)					(44,624,000)
Adjustment Due to Change in Ownership of Consolidated Subsidiaries	(295,000)	479,000				(774,000)
Retirement of treasury stock, shares				(1,472,000)			(1,472,000)
Retirement of treasury stock	0	(28,446,000)		$ 28,937,000			$ (491,000)
Balance, Shares at Dec. 31, 2015							238,949,000	18,805,000
Balance at Dec. 31, 2015	3,974,556,000	2,524,420,000	1,059,240,000		(67,905,000)	456,224,000	$ 2,389,000	$ 188,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss), net of amounts attributable to redeemable noncontrolling interest	(152,324,000)		(158,402,000)			6,078,000
Other comprehensive income (loss), net of tax	53,510,000				53,495,000	15,000
Common Stock Dividends	(88,452,000)		(88,452,000)
Conversion of Class B to Class A Shares, shares							17,000	(17,000)
Conversion of Class B to Class A shares	0						$ 0	$ 0
Cost incurred for planned reclassification of Class B to Class A shares	(3,896,000)	(3,896,000)
Issuance of Class A shares in exchange for Convertible Senior Notes, shares							9,000
Issuance of Class A shares in exchange for Convertible Senior Notes	186,000	186,000					$ 0
Restricted stock and performance shares vested, shares							1,267,000
Restricted stock and performance shares vested	$ 0	(12,000)					$ 12,000
Repurchase of Class A common shares, shares	(390,703)						(390,000)
Repurchase of Class A common shares	$ (7,945,000)	(7,942,000)					$ (3,000)
Exercise of stock options and write-off of deferred tax asset related to expired stock options, shares							86,000
Exercise of stock options and write-off of deferred tax asset related to expired stock options	1,158,000	1,157,000					$ 1,000
Stock-based compensation	25,463,000	25,463,000
Acquisition of partner's noncontrolling interest in consolidated subsidiaries	(36,185,000)	(56,101,000)				19,916,000
Contributions from noncontrolling interests	50,506,000					50,506,000
Distributions to noncontrolling interests	(31,578,000)					(31,578,000)
Balance, Shares at Dec. 31, 2016				0			239,938,000	18,788,000
Balance at Dec. 31, 2016	3,784,999,000	2,483,275,000	812,386,000	$ 0	(14,410,000)	501,161,000	$ 2,399,000	$ 188,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss), net of amounts attributable to redeemable noncontrolling interest	215,036,000		206,030,000			9,006,000
Other comprehensive income (loss), net of tax	5,861,000				5,847,000	14,000
Common Stock Dividends	(121,610,000)		(121,610,000)
Conversion of Class B to Class A Shares, shares							24,612,000	(18,788,000)
Conversion of Class B to Class A shares	0	(58,000)					$ 246,000	$ (188,000)
Cost incurred for planned reclassification of Class B to Class A shares	(9,305,000)	(9,305,000)
Issuance of Class A shares in exchange for Convertible Senior Notes, shares							0
Issuance of Class A shares in exchange for Convertible Senior Notes	1,000	1,000					$ 0
Restricted stock and performance shares vested, shares							818,000
Restricted stock and performance shares vested	$ 0	(8,000)					$ 8,000
Repurchase of Class A common shares, shares	(272,121)						(272,000)
Repurchase of Class A common shares	$ (6,082,000)	(6,080,000)					$ (2,000)
Exercise of stock options and write-off of deferred tax asset related to expired stock options, shares	90,545						91,000
Exercise of stock options and write-off of deferred tax asset related to expired stock options	$ 1,498,000	1,497,000					$ 1,000
Issuance of Class A common stock under the deferred compensation plan for non-employee director, shares							13,000
Issuance of Class A common stock under the deferred compensation plan for non-employee director	309,000	309,000					$ 0
Stock-based compensation	26,884,000	26,884,000
Exchange of 2006 Class A Common Units for Class A shares, shares							143,000
Exchange of 2006 Class A Common Units for Class A shares	0	7,287,000				(7,288,000)	$ 1,000
Noncontrolling Interest, Decrease from Exchange of Units for Rental Property	(12,232,000)	22,805,000				(35,037,000)
Acquisition of partner's noncontrolling interest in consolidated subsidiaries	0	10,931,000				(10,931,000)
Contributions from noncontrolling interests	23,168,000					23,168,000
Distributions to noncontrolling interests	(63,810,000)					(63,810,000)
Balance, Shares at Dec. 31, 2017				0			265,343,000	0
Balance at Dec. 31, 2017	$ 3,844,717,000	$ 2,537,538,000	$ 896,806,000	$ 0	$ (8,563,000)	$ 416,283,000	$ 2,653,000	$ 0

Consolidated Statements of Equ8

Consolidated Statements of Equity (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Noncontrolling Interest
Net loss attributable to redeemable noncontrolling interest	$ 0	$ 776,000	$ 16,962,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net earnings (loss)	$ 215,036,000	$ (153,100,000)	$ 492,338,000
Depreciation and amortization	248,353,000	250,848,000	252,925,000
Amortization of mortgage procurement costs	5,550,000	5,719,000	7,549,000
Impairment of real estate	44,288,000	156,825,000	451,434,000
Impairment of unconsolidated entities	10,600,000	306,400,000	13,844,000
Write-offs of abandoned development projects and demolition costs	1,596,000	10,348,000	4,430,000
Loss on extinguishment of debt	2,961,000	32,580,000	65,086,000
Net gain (loss) on disposition of full or partial interest in development projects, net of tax	113,000	(136,117,000)	0
Net gain on disposition of full or partial interest in rental properties, net of tax	(18,800,000)	(121,284,000)	(1,067,000)
Gain on disposition of rental property in deed-in-lieu transaction	(29,845,000)	0	0
Gain on change in control of interests	0	0	(486,279,000)
Deferred income tax expense (benefit)	(28,200,000)	493,000	(583,917,000)
Net gain on disposition of interest in unconsolidated entities	(25,163,000)	(29,701,000)	(22,313,000)
Net gain on disposition of interest in unconsolidated entities	110,221,000	13,166,000	20,293,000
Stock-based compensation expense	18,738,000	19,802,000	24,118,000
Amortization and mark-to-market adjustments of derivative instruments	1,904,000	3,053,000	(2,886,000)
Cash distributions from operations of unconsolidated entities	76,683,000	71,646,000	60,029,000
Non-cash operating expenses and deferred taxes included in discontinued operations	0	(309,000)	18,569,000
Loss from unconsolidated entities included in discontinued operations	0	1,400,000	40,760,000
Gain on disposition included in discontinued operations, net of tax	0	(49,353,000)	0
Decrease in land inventory	15,213,000	878,000	6,776,000
(Increase) decrease in accounts receivable	(12,922,000)	10,375,000	(6,422,000)
(Increase) decrease in other assets	(2,220,000)	12,386,000	(27,283,000)
Increase (decrease) in accounts payable, accrued expenses and other liabilities	17,662,000	(86,872,000)	(11,922,000)
Net cash provided by operating activities	431,326,000	292,851,000	275,476,000
Cash Flows from Investing Activities
Capital expenditures	(435,841,000)	(576,556,000)	(536,569,000)
Capital expenditures of assets included in discontinued operations	0	(690,000)	(20,811,000)
Acquisitions	0	0	(397,275,000)
Payment of lease procurement costs	(11,569,000)	(11,692,000)	(12,662,000)
Increase in notes receivable	(38,357,000)	(28,846,000)	(31,211,000)
Payments on notes receivable	72,338,000	58,000,000	56,448,000
Decrease in restricted cash	11,839,000	9,250,000	111,257,000
Cash held at Arena upon disposition	0	(28,041,000)	0
Proceeds from disposition of rental properties or development projects	88,526,000	596,837,000	35,950,000
Contributions to unconsolidated entities	(95,447,000)	(140,309,000)	(115,496,000)
Distributions from unconsolidated entities	133,840,000	45,339,000	24,599,000
Net cash used in investing activities	(274,671,000)	(76,708,000)	(885,770,000)
Cash Flows from Financing Activities
Proceeds from nonrecourse mortgage debt and notes payable	210,467,000	555,770,000	312,841,000
Principal payments on nonrecourse mortgage debt and notes payable	(156,285,000)	(919,136,000)	(523,346,000)
Borrowings on revolving credit facility	0	20,500,000	111,850,000
Payments on revolving credit facility	0	(20,500,000)	(111,850,000)
Borrowings on term loan facility	0	335,000,000	0
Redemption of Senior Notes due 2018 & 2020	0	157,644,000	0
Proceeds from issuance of Class A common stock, net of $34,438 of transaction costs	0	0	806,500,000
Proceeds received from termination of convertible senior note hedge	0	0	17,818,000
Payments to noteholders related to exchange of convertible senior notes	0	(24,376,000)	(63,135,000)
Transaction costs related to exchanges of Senior Notes for Class A common stock	0	(2,460,000)	(6,950,000)
Payments of Stock Issuance Costs	(11,266,000)	0	0
Payment of deferred financing costs	(2,768,000)	(7,172,000)	(16,808,000)
Purchase of treasury stock	0	0	(5,543,000)
Repurchase of Class A common shares	(6,082,000)	(7,945,000)	(579,000)
Exercise of stock options	1,498,000	1,158,000	1,488,000
Dividends paid to stockholders	(121,610,000)	(88,452,000)	0
Net distributions to redeemable noncontrolling interests	0	0	(6,098,000)
Acquisitions of noncontrolling interests	0	(39,395,000)	(312,000)
Contributions from noncontrolling interests	23,168,000	50,328,000	106,244,000
Distributions to noncontrolling interests	(64,136,000)	(30,920,000)	(44,624,000)
Net cash (used in) provided by financing activities	(127,014,000)	(335,244,000)	577,496,000
Net increase (decrease) in cash and equivalents	29,641,000	(119,101,000)	(32,798,000)
Cash and equivalents at beginning of period (including cash held for sale)	174,619,000	293,720,000	326,518,000
Cash and equivalents at end of period (including cash held for sale)	$ 204,260,000	$ 174,619,000	$ 293,720,000

Consolidated Statements of Ca10

Consolidated Statements of Cash Flows (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Cash Flows Parentheticals [Abstract]
Payments of Stock Issuance Costs	$ 34,438

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Accounting Policies	Summary of Significant Accounting Policies General Forest City Realty Trust, Inc. (with its subsidiaries, the “Company”) principally engages in the operation, development, management and acquisition of office, apartment and retail real estate and land throughout the United States. The Company had approximately $8.1 billion of consolidated assets in 20 states and the District of Columbia at December 31, 2017 . The Company’s core markets include Boston, Chicago, Dallas, Denver, Los Angeles, Philadelphia, and the greater metropolitan areas of New York City, San Francisco and Washington D.C. The Company has regional offices in Boston, Dallas, Denver, Los Angeles, New York City, San Francisco, Washington, D.C. , and the Company’s corporate headquarters in Cleveland, Ohio. The Company is organized around real estate operations, real estate development and corporate support service functions. Real Estate Operations represents the performance of the Company’s core rental real estate portfolio and is comprised of the following reportable operating segments: • Office - owns, acquires and operates office and life science buildings. • Apartments - owns, acquires and operates upscale and middle-market apartments and adaptive re-use developments. • Retail - owns, acquires and operates amenity retail within our mixed-use properties, and remaining regional malls and specialty/urban retail centers. The remaining reportable operating segments consist of the following: • Development - develops and constructs office and life science buildings, apartments, condominiums, amenity retail and mixed-use projects. The Development segment includes recently opened operating properties prior to stabilization and the horizontal development and sale of land to residential, commercial and industrial customers primarily at its Stapleton project in Denver, Colorado. • Corporate - provides executive oversight and various support services for Operations, Development and Corporate employees. • Other - owned and operated non-core investments, including the Barclays Center, a sports and entertainment arena located in Brooklyn, New York (“Arena”) (sold in January 2016), the Company’s equity method investment in the Brooklyn Nets (the “Nets”) (sold in January 2016), and military housing operations (sold in February 2016). Segment Transfers The Development segment includes projects in development and projects under construction along with recently opened operating properties prior to stabilization. Projects will be reported in their applicable operating segment (Office, Apartments or Retail) beginning on January 1 of the year following stabilization. Therefore, the Development segment will continue to report results from recently opened properties until the year-end following initial stabilization. The Company generally defines stabilized properties as achieving 92% or greater occupancy or having been open and operating for one or two years, depending on the size of the project. Once a stabilized property is transferred to the applicable Operations segment on January 1, it will be considered “comparable” beginning with the next January 1, as that will be the first time the property is stabilized in both periods presented. REIT Conversion On January 13, 2015, the board of directors of Forest City Enterprises, Inc., the Company’s predecessor, approved a plan to pursue conversion to real estate investment trust (“REIT”) status. On May 29, 2015, Forest City Enterprises, Inc. formed the Company as a Maryland corporation and wholly-owned subsidiary of Forest City Enterprises, Inc. On October 20, 2015, the stockholders of Forest City Enterprises, Inc. approved and adopted the merger agreement that implemented the restructuring of Forest City Enterprises, Inc. into a holding company so as to facilitate its conversion to a REIT. Pursuant to the merger agreement, effective as of 11:59 pm, Eastern Time, on December 31, 2015 (the “Effective Time”), (i) a wholly-owned subsidiary of the Company merged with and into Forest City Enterprises, Inc., with Forest City Enterprises, Inc. as the surviving corporation, (ii) each outstanding share of Forest City Enterprises, Inc. Class A common stock, par value $.33 1/3 per share, and Class B common stock, par value $.33 1/3 per share, automatically converted into one share of Forest City Realty Trust, Inc. Class A common stock, $.01 par value per share, and Class B common stock, $.01 par value per share, respectively, (iii) Forest City Enterprises, Inc. became a wholly-owned subsidiary of the Company and (iv) the Company became the publicly-traded New York Stock Exchange-listed parent company that succeeded to and continued to operate substantially all of the existing businesses of Forest City Enterprises, Inc. and its subsidiaries. In addition, each share of Class A common stock of Forest City Enterprises, Inc. held in treasury at December 31, 2015 ceased to be outstanding at the Effective Time of the Merger, and a corresponding adjustment was recorded to Class A common stock and additional paid-in capital. Immediately following the merger, Forest City Enterprises, Inc. converted into a Delaware limited partnership named “Forest City Enterprises, L.P.” (the “Operating Partnership”). In this annual report on Form 10-K, unless otherwise specifically stated or the context otherwise requires, all references to “the Company,” “Forest City,” “we,” “our,” “us” and similar terms refer to Forest City Enterprises, Inc. and its consolidated subsidiaries prior to the Effective Time and Forest City Realty Trust, Inc. and its consolidated subsidiaries, including the Operating Partnership, as of the Effective Time and thereafter. Company Operations The Company is organized as a Real Estate Investment Trust (“REIT”) for federal income tax purposes. The Company holds substantially all of its assets, and conducts substantially all of its business, through the Operating Partnership. The Company is the sole general partner of the Operating Partnership and, as of December 31, 2017 , owns all of the limited partnership interests directly or indirectly in the Operating Partnership. The Company holds and operates certain of its assets through one or more taxable REIT subsidiaries (“TRSs”). A TRS is a subsidiary of a REIT subject to applicable corporate income tax. The Company’s use of TRSs enables it to continue to engage in certain businesses while complying with REIT qualification requirements and allows the Company to retain income generated by these businesses for reinvestment without the requirement of distributing those earnings. The primary businesses held in TRSs include 461 Dean Street, an apartment building in Brooklyn, New York , South Bay Galleria (sold in December 2017) , Antelope Valley Mall (sold in January 2018), Mall at Robinson (sold in February 2018) and Charleston Town Center , regional malls in Redondo Beach, California, Palmdale, California, Pittsburgh, Pennsylvania and Charleston, West Virginia, respectively, Pacific Park Brooklyn project, land development operations, Barclays Center arena (sold in January 2016), the Nets (sold in January 2016), and military housing operations (sold in February 2016). In the future, the Company may elect to reorganize and transfer certain assets or operations from its TRSs to other subsidiaries, including qualified REIT subsidiaries. Principles of Consolidation The accompanying consolidated financial statements include the accounts of Forest City Realty Trust, Inc., its wholly-owned subsidiaries and entities in which it has a controlling interest in accordance with accounting principles generally accepted in the United States of America (“GAAP”). All intercompany balances and transactions have been eliminated in consolidation. The accounting guidance for consolidation of variable interest entities (“VIEs”) requires an ongoing reassessment of determining whether a variable interest gives a company a controlling financial interest in a VIE. VIEs are entities in which the equity investors do not have sufficient equity at risk to finance their endeavors without additional financial support or the holders of the equity investment at risk do not have a controlling financial interest. The Company continuously reassesses whether or not it has the (a) power to direct the activities of the VIE that most significantly affect its economic performance and (b) the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions in certain circumstances that affect amounts reported in the accompanying consolidated financial statements and related notes. Some of the critical estimates made by the Company include, but are not limited to, determination of the primary beneficiary of VIEs, estimates of useful lives for long-lived assets, reserves for collection on accounts and notes receivable and other investments, gain on change in control of interests, impairment of real estate and other-than-temporary impairments on equity method investments. Actual results could differ from those estimates. Reclassifications Certain prior period amounts in the accompanying consolidated financial statements have been reclassified to conform to the current year’s presentation. New Accounting Guidance In March 2016, the Financial Accounting Standards Board (“FASB”) issued an amendment to the accounting guidance to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification awards as either equity or liabilities, and classification on the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. The adoption of this guidance effective January 1, 2017 did not have a material impact on the Company’s consolidated financial statements. In August 2016, the FASB issued an amendment to the accounting guidance on the classification of certain transactions on the statement of cash flows where diversity in practice previously existed. The guidance addresses certain specific cash flow issues, including, but not limited to, debt prepayment or debt extinguishment costs and distributions received from equity method investments. This guidance is effective for fiscal years, and for interim reporting periods within those fiscal years, beginning after December 15, 2017. Early adoption was permitted, and the Company elected to adopt this guidance using the retrospective transition method effective January 1, 2017. The adoption of this guidance did not have a material impact the Company’s Consolidated Statements of Cash Flows. In January 2017, the FASB issued an amendment to the accounting guidance for business combinations to clarify the definition of a business. The objective of this guidance is to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. This guidance is effective for annual periods beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted, and the Company has elected to adopt this guidance effective January 1, 2017 on a prospective basis. The impact on the Company’s consolidated financial statements resulting from the adoption of this guidance will depend on the Company’s level of acquisitions, but will most likely increase the number of acquisitions accounted for as asset acquisitions rather than business combinations. The following new accounting pronouncements will be adopted on January 1, 2018: In May 2014, the FASB issued an amendment to the accounting guidance for revenue from contracts with customers. The core principle of this guidance is an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance defines steps an entity should apply to achieve the core principle. This guidance is effective for annual reporting periods beginning after December 15, 2017 and interim reporting periods within that annual period and allows for both retrospective and modified retrospective methods of adoption. The Company will adopt this guidance as of January 1, 2018 using the modified retrospective method. Rental revenue from lease contracts represents a significant portion of the Company’s total revenues and is a specific scope exception provided by this guidance. However, common area maintenance and other tenant reimbursable expenses provided to the lessee are considered a non-lease component and will be required to be separated from rental revenue and recorded on a separate financial statement line item upon adoption of the new accounting guidance on leases discussed below. The Company has completed its analysis and has concluded the adoption of this guidance will not result in a material impact on the Company’s consolidated financial statements or disclosures. In November 2016, the FASB issued an amendment to the accounting guidance on the classification and presentation of changes in restricted cash on the statement of cash flows. The guidance requires restricted cash to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown in the statement of cash flows. This guidance is effective for fiscal years, and for interim reporting periods within those fiscal years, beginning after December 15, 2017. The Company will adopt this guidance as of January 1, 2018 using the retrospective transition method. The adoption of this guidance will significantly increase the combined beginning and ending period cash and restricted cash balances as presented and will remove the effects of the change in restricted cash as previously presented in Company’s Consolidated Statements of Cash Flows. In February 2017, the FASB issued an amendment to the accounting guidance on the derecognition of nonfinancial assets. The guidance clarifies the definition of an in substance nonfinancial asset and the recognition of gains and losses from the transfer of nonfinancial assets and for partial sales of nonfinancial assets, which would include real estate. This guidance is effective for fiscal years, and for interim reporting periods within those fiscal years, beginning after December 15, 2017. The Company will adopt this guidance using the modified retrospective method on January 1, 2018. The impact on the Company’s consolidated financial statements resulting from the adoption of this guidance will depend on the level of real estate sales. In August 2017, the FASB issued an amendment to the accounting guidance on derivatives and hedging activities. The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. The transition method is a modified retrospective approach that will require the Company to recognize the cumulative effect of initially applying the guidance as an adjustment to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings as of the beginning of the fiscal year that an entity adopts the update. The Company has elected to early adopt the guidance on January 1, 2018. The adoption of this guidance will not have a material impact on the Company’s consolidated financial statements. The following new accounting pronouncement will be adopted on its respective effective date: In February 2016, the FASB issued an amendment to the accounting guidance on leases. This guidance sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new guidance requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to the current guidance for operating leases. The new guidance requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. The guidance is expected to impact the Company’s consolidated financial statements as the Company has certain operating and land lease arrangements for which it is the lessee. The new guidance supersedes the previous leases accounting standard. The guidance is effective on January 1, 2019. The adoption of the new guidance is expected to have an impact on the consolidated financial statements as the Company has material ground lease arrangements, as well as other lease agreements. In addition, the Company believes it will be precluded from capitalizing its internal leasing costs, as the costs are not expected to be directly incremental to the successful execution of a lease, as required by the new guidance. The Company is in the process of evaluating the impact of this guidance. In January 2018, the FASB issued a proposal for comment that would make targeted improvements to the new accounting guidance on leases providing lessors with a practical expedient by class of underlying assets to not separate non-lease components from the lease component. Such practical expedient would be limited to circumstances in which (i) the timing and pattern of revenue recognition are the same for the non-lease component and the related lease component and (ii) the combined single lease component would be classified as an operating lease. If the exposed practical expedient is issued in its existing form, the Company expects to elect the practical expedient which would allow the Company the ability to combine the lease and non-lease components if the underlying asset meets the two criteria above. Acquisition of Rental Properties Upon acquisition of a rental property, the purchase price is allocated to net tangible and identified intangible assets acquired based on estimated fair values. Above-market and below-market in-place lease values are recorded based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) the Company’s estimated fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease. Above-market lease values are amortized as a reduction of rental revenues (or rental expense for ground leases in which the Company is the lessee) over the remaining non-cancelable terms of the respective leases. Below-market lease values are amortized as an increase to rental revenues (or rental expense for ground leases in which the Company is the lessee) over the remaining non-cancelable terms of the respective leases, including any fixed-rate renewal periods that are probable of being exercised. For the Company’s below-market lease and in-place lease intangibles remaining at December 31, 2017 and 2016 , the Company assumed fixed rate renewals for the in-place leases deemed to be below market and include the assumed renewals in the calculation of intangible asset values and related amortization period. Intangible assets also include amounts representing the value of tenant relationships and in-place leases based on the Company’s evaluation of each tenant’s lease and its overall relationship with the respective tenant. The Company estimates the cost to execute leases with terms similar to in-place leases, including leasing commissions, legal and other related expenses. This intangible asset is amortized to expense over the remaining term of the respective lease. The Company’s estimates of value are made using methods similar to those used by independent appraisers or by using independent appraisals. Factors considered by the Company in this analysis include an estimate of the carrying costs during the expected lease-up periods, current market conditions and costs to execute similar leases. In estimating carrying costs, the Company includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the expected lease-up periods, which primarily range from three to twelve months. The Company also considers information obtained about each property as a result of its pre-acquisition due diligence, marketing and leasing activities in estimating the fair value of the tangible and intangible assets acquired. The Company also uses the information obtained as a result of its pre-acquisition due diligence in considering any conditional asset retirement obligations, and when necessary, will record a conditional asset retirement obligation as part of its purchase price. The value of in-place leases is amortized over the remaining non-cancelable term of the respective leases and any fixed-rate renewal periods deemed probable. The Company considers whether there is a value associated with a tenant relationship intangible asset. However, based on the nature of the assets typically acquired, it is rare for there to be a value assigned to this intangible asset. In the event a lease is terminated, the unamortized portion of each related intangible is charged to income or expense, as applicable. Cash and Equivalents The Company considers all highly liquid instruments purchased with a maturity of three months or less to be cash equivalents. Cash equivalents are stated at cost, which approximates market value. The Company maintains operating cash and reserves for replacement balances in financial institutions which, from time to time, may exceed federally insured limits. The Company periodically assesses the financial condition of these institutions and believes the risk of loss is minimal. Cash flows associated with items intended as hedges of identifiable transactions or events are classified in the same category as the cash flows from the items being hedged. Cash flows from derivatives not designated as cash flow or fair value hedges are generally classified in the investing section in the Consolidated Statements of Cash Flows. Cash flows associated with lease procurement costs are classified as investing activities and consist primarily of lease commissions and related legal fees associated with procuring first generation tenants under long-term lease agreements for office buildings, regional malls or specialty retail centers. The Company primarily incurs these costs during the development phase of the project and they are integral to starting construction and ultimately completing the project. Management views these lease procurement costs as part of the initial investment to obtain long-term cash flow. Restricted Cash Restricted cash represents amounts for debt service payments, taxes and insurance, collateral, security deposits, capital replacement, improvement and operating reserves, bond funds, and development and construction escrows. Allowance for Doubtful Accounts Allowances against notes and accounts receivables are based on management’s estimate of amounts that ultimately will not be realized from cash receipts or any applicable collateral. The Company’s notes receivable are evaluated individually for allowance purposes. As of December 31, 2017 , each of the Company’s notes receivables is performing and we expect to collect amounts as they come due, and, as such, interest income on the notes receivables is accrued as earned. If the estimate of expected future cash flows does not accurately reflect actual events, the allowance may be over or understated. Management exercises judgment in establishing these allowances and considers payment history and current credit status in developing these estimates. The Company also maintains an allowance for receivables arising from the straight-lining of rents.This receivable arises from earnings recognized in excess of amounts currently due under lease agreements. The allowance against the straight-line rent receivable is based on historical experience with early lease terminations as well as specific review of significant tenants and tenants having known financial difficulties. There is a risk the estimate of the expected activity of current tenants may not accurately reflect future events. If the estimate does not accurately reflect future tenant vacancies, the allowance for straight-line rent receivable may be over or understated. Investments in Unconsolidated Entities Investments in unconsolidated entities include investments in and advances to unconsolidated entities and cash distributions and losses in excess of investments in unconsolidated entities the Company does not control and/or is not deemed to be the primary beneficiary. The Company accounts for its investments in unconsolidated entities using the equity method of accounting whereby the cost of an investment is adjusted for the Company’s share of income or loss from the date of acquisition, increased for equity contributions made and reduced by distributions received. The income or loss for each unconsolidated entity is allocated in accordance with the provisions of the applicable operating agreements, including distribution priorities, which may change upon the achievement of certain return thresholds and may differ from the legal ownership interest held. Differences between the Company’s carrying value of its investment in unconsolidated entities and the Company’s underlying equity of such unconsolidated entities are amortized over the respective lives of the underlying assets or liabilities, as applicable. Certain investments in unconsolidated entities’ share of cumulative allocated losses and cash distributions received exceeds its cumulative allocated share of income and equity contributions. As a result, the carrying value of certain investments in unconsolidated entities is negative, based on the Company’s ongoing potential funding requirements. Unconsolidated entities with negative carrying values are included in cash distributions and losses in excess of investments in unconsolidated entities in the Consolidated Balance Sheets. The Company may provide funding in excess of its legal ownership. These fundings are typically interest-bearing or entitle the Company to a preference on and of such advances of property cash flows and are included in investments in and advances to unconsolidated entities. Other Assets Other assets include costs incurred with obtaining the revolving credit facility financing, which are amortized over the life of the related facility and costs incurred with leasing space to tenants, which are amortized using the straight-line method over the terms of the related leases. Intangible Assets Upon an acquisition of a rental property, the Company records intangible assets at their estimated fair value separate and apart from goodwill. The Company amortizes identified intangible assets with finite lives on a straight-line basis over the period the assets are expected to contribute directly or indirectly to the future cash flows of the acquired property. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate their carrying amount may not be recoverable. An impairment loss is recognized if the carrying amount of an intangible asset is not recoverable and its carrying amount exceeds its estimated fair value. Variable Interest Entities As of December 31, 2017 , the Company determined it was the primary beneficiary of 44 VIEs. The creditors of the consolidated VIEs do not have recourse to the Company’s general credit. As of December 31, 2017 , the Company determined it was not the primary beneficiary of 38 VIEs and accounts for these interests as equity method investments. The maximum exposure to loss of these unconsolidated VIEs is limited to $188,000,000 , the Company’s investment balances at December 31, 2017 . Derivative Instruments and Hedging Activities Derivatives are recorded at fair value. Accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and whether it meets the hedge accounting requirements. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Hedge accounting generally provides for the matching of gain or loss recognition on the instrument with the recognition of the change in the fair value of the hedged asset or liability attributable to the hedged risk (in a fair value hedge) or the earnings effect of the hedged forecasted transactions (in a cash flow hedge). The Company may enter into derivative contracts intended to economically hedge certain interest rate risk, even though the contracts do not qualify for or the Company has elected not to apply hedge accounting. Accumulated Other Comprehensive Loss The following table summarizes the components of accumulated other comprehensive loss (“accumulated OCI”): December 31, 2017 2016 2015 (in thousands) Unrealized losses on foreign currency translation $ — $ — $ 95 Unrealized losses on interest rate derivative contracts (1) 8,612 14,473 67,888 8,612 14,473 67,983 Noncontrolling interest (49 ) (63 ) (78 ) Accumulated other comprehensive loss $ 8,563 $ 14,410 $ 67,905 The following table summarizes the changes, net of tax and noncontrolling interest, of accumulated OCI by component: Foreign Currency Translation Interest Rate Contracts Total (in thousands) Balance, January 1, 2015 $ (84 ) $ (58,762 ) $ (58,846 ) Gain (loss) recognized in accumulated OCI 24 (6,445 ) (6,421 ) Loss reclassified from accumulated OCI — 29,013 29,013 One-time adjustment to deferred taxes on OCI related to REIT conversion (3) (35 ) (31,616 ) (31,651 ) Total other comprehensive income (loss) (11 ) (9,048 ) (9,059 ) Balance, December 31, 2015 $ (95 ) $ (67,810 ) $ (67,905 ) Gain (loss) recognized in accumulated OCI 95 (9,414 ) (9,319 ) Loss reclassified from accumulated OCI — 62,814 62,814 Total other comprehensive income 95 53,400 53,495 Balance, December 31, 2016 $ — $ (14,410 ) $ (14,410 ) Gain recognized in accumulated OCI — 476 476 Loss reclassified from accumulated OCI — 5,371 5,371 Total other comprehensive income — 5,847 5,847 Balance, December 31, 2017 $ — $ (8,563 ) $ (8,563 ) (1) Includes unrealized losses on interest rate swaps accounted for as hedges held by certain of the Company’s equity method investees. The following table summarizes losses reclassified from accumulated OCI and their location on the Consolidated Statements of Operations: Accumulated OCI Components Loss Reclassified from Accumulated OCI Location on Consolidated Statements of Operations (in thousands) Year Ended December 31, 2017 Interest rate contracts $ 2,817 Interest expense Interest rate contracts 2,568 Earnings from unconsolidated entities 5,385 Total before income tax and noncontrolling interest (14 ) Noncontrolling interest $ 5,371 Loss reclassified from accumulated OCI Year Ended December 31, 2016 Interest rate contracts $ 34,889 Interest expense Interest rate contracts 24,635 Reclassification adjustment for interest rate swap breakage fee Interest rate contracts 113 Net gain (loss) on disposition of full or partial interest in rental properties, net of tax Interest rate contracts 3,192 Earnings from unconsolidated entities 62,829 Total before income tax and noncontrolling interest (15 ) Noncontrolling interest $ 62,814 Loss reclassified from accumulated OCI Year Ended December 31, 2015 Interest rate contracts $ 37,852 Interest expense Interest rate contracts (900 ) Gain on change

Accounts Receivable, Net

Accounts Receivable, Net	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Accounts Receivable, Net	Accounts Receivable, Net The following table summarizes the components of accounts receivable, net: December 31, 2017 2016 (in thousands) Straight-line rent - tenants $ 110,201 $ 119,366 Accounts receivable - tenants 11,206 13,263 Alternative minimum tax (“AMT”) credit receivable 28,100 — Other 78,912 81,258 228,419 213,887 Allowance for doubtful accounts (3,397 ) (5,324 ) Total $ 225,022 $ 208,563 See Note V - Income Taxes for additional information on the AMT credit receivable.

Notes Receivable

Notes Receivable	12 Months Ended
	Dec. 31, 2017
Notes Receivable [Abstract]
Financing Receivables [Text Block]	Notes Receivable The following table summarizes the components of interest bearing notes receivable: December 31, Weighted Average Interest Rate 2017 2016 Date of Maturity (in thousands) Stapleton advances $ 128,676 $ 141,034 Various 8.53% The Nets sale 125,100 125,100 January 2021 4.50% Barclays Center sale 92,600 92,600 January 2019 4.50% QIC 36,935 — April 2019 4.25% Other 15,474 24,429 Various 4.82% Total $ 398,785 $ 383,163 Stapleton Advances The Company has made interest-bearing advances to the Park Creek Metropolitan District for certain infrastructure at its Stapleton project. The Company recorded $14,066,000 , $12,781,000 and $13,892,000 of interest income related to these advances for the years ended December 31, 2017 , 2016 and 2015 , respectively. QIC During the year ended December 31, 2017, in connection with the disposal of the Company’s regional mall portfolio to Queensland Investment Corporation (“QIC”), the Company recorded a note receivable for a portion of the proceeds. The Company anticipates providing up to $150,000,000 of financing in connection with this transaction as additional regional mall assets are disposed of, all of which is expected to mature in 2019. Barclays Center and the Nets Sale During the year ended December 31, 2016, the Company completed the sale of the Nets and Barclays Center and recorded a note receivable for a portion of the proceeds.

Investments in Unconsolidated E

Investments in Unconsolidated Entities	12 Months Ended
	Dec. 31, 2017
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]
Investments in Unconsolidated Entities	Investments in Unconsolidated Entities The following table is a reconciliation of members’ and partners’ equity to the Company’s carrying value: December 31, 2017 2016 (in thousands) Total members’ and partners’ equity $ 1,478,172 $ 1,428,242 Equity of other members and partners 1,021,051 998,199 Company’s net investment in unconsolidated entities 457,121 430,043 Basis differences (1) (25,838 ) (16,356 ) Advances to and on behalf of affiliates (4,803 ) 500 Total Investments in Unconsolidated Entities, net $ 426,480 $ 414,187 Assets - Investments in and advances to unconsolidated entities $ 550,362 $ 564,779 Liabilities - Cash distributions and losses in excess of investments in unconsolidated entities (123,882 ) (150,592 ) Total Investments in Unconsolidated Entities, net $ 426,480 $ 414,187 (1) Represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the equity method venture level, which is typically amortized over the life of the related assets or liabilities. Basis differences relate to certain acquisition, transaction and other costs, as well as other-than-temporary impairments not reflected at the equity method venture level. The following table presents summarized financial information for equity method investments: (Combined 100%) December 31, 2017 2016 (in thousands) Balance Sheets: Real Estate Completed rental properties $ 6,577,155 $ 6,303,559 Projects under construction and development 1,375,381 1,817,074 Land inventory 36,682 51,142 Total Real Estate 7,989,218 8,171,775 Less accumulated depreciation (1,462,177 ) (1,525,369 ) Real Estate, net 6,527,041 6,646,406 Cash and equivalents 127,877 144,790 Other restricted cash 187,293 230,163 Other assets 482,308 541,145 Total Assets $ 7,324,519 $ 7,562,504 Nonrecourse mortgage debt and notes payable, net $ 5,425,032 $ 5,635,343 Other liabilities 421,315 498,919 Members’ and partners’ equity 1,478,172 1,428,242 Total Liabilities and Members’ and Partners’ Equity $ 7,324,519 $ 7,562,504 (Combined 100%) Years Ended December 31, 2017 2016 2015 (in thousands) Operations: Revenues $ 958,696 $ 809,209 $ 1,100,094 Operating expenses (494,114 ) (343,036 ) (491,804 ) Depreciation and amortization (198,706 ) (225,712 ) (244,126 ) Interest and other income 17,637 16,297 19,721 Net gain (loss) on disposition of full or partial interest in rental properties 49,250 (24,475 ) — Interest expense including extinguishment of debt (211,056 ) (216,198 ) (314,332 ) Earnings from continuing operations $ 121,707 $ 16,085 $ 69,553 Discontinued operations: Operating loss from rental properties — (7,561 ) (64,766 ) Discontinued operations subtotal — (7,561 ) (64,766 ) Net earnings (loss) $ 121,707 $ 8,524 $ 4,787 Company’s portion of net earnings 25,163 29,701 22,313 Impairment of investments in unconsolidated entities (10,600 ) (306,400 ) (13,844 ) Company’s portion of gain on disposition of full or partial interest in rental properties 32,316 13,166 — Net gain on disposition of full or partial interest in equity method investments 77,905 — 20,293 Net earnings from unconsolidated entities $ 124,784 $ (263,533 ) $ 28,762 Net Gain on Disposition of Full or Partial Interest in Rental Properties and Equity Method Investments The following table summarizes gains and losses on the disposition or partial disposition of unconsolidated entities which are included in equity from unconsolidated entities: Years Ended December 31, 2017 2016 2015 (in thousands) Net gain (loss) on disposition of full or partial interest in rental properties: Federally assisted housing apartment communities Various $ 27,942 $ — $ — Specialty Retail Centers: Shops at Bruckner Boulevard Bronx, New York 21,308 — — Steinway Street Theaters Queens, New York — 29,489 — Mesa del Sol (Land Inventory) (1) Albuquerque, New Mexico — (53,964 ) — Total gain (loss) on disposition of full or partial interest in rental properties $ 49,250 $ (24,475 ) $ — Company’s portion of gain on disposition of full or partial interest in rental properties $ 32,316 $ 13,166 $ — Net gain (loss) on disposition of full or partial interest in equity method investments: Apartment Communities: Federally assisted housing Various $ 49,800 $ — $ — Newport Landing Coventry Township, Ohio — — 5,765 Eaton Ridge Sagamore Hills, Ohio — — 4,745 Arbor Glen Twinsburg, Ohio — — 3,422 Parkwood Village Brunswick, Ohio — — 2,817 Sutton Landing Brimfield, Ohio — — 2,535 South Bay Galleria (Regional Mall) Redondo Beach, CA 28,180 — — Suburban Cleveland office properties Beachwood, OH 1,437 — — Other (1,512 ) — 1,009 Total gain on disposition of full or partial interest in equity method investments $ 77,905 $ — $ 20,293 (1) Represents the loss recorded at the joint venture level upon disposition of real estate. Prior to the year ended December 31, 2016, the Company impaired its investment in the joint venture and therefore was not allocated a material portion of this loss recorded at the joint venture level. During the year ended December 31, 2017 , the Company completed the sale of its ownership interest in unconsolidated federally assisted housing (“FAH”) apartment communities, consisting of 6,116 units. The dispositions resulted in net cash proceeds of $59,080,000 . During the year ended December 31, 2017 , the Company sold its ownership interest in South Bay Galleria , an unconsolidated regional mall in Redondo Beach, California. The sale generated net cash proceeds of $58,530,000 at the Company’s ownership share. During the year ended December 31, 2017 , the Company sold its ownership interest in Shops at Bruckner Boulevard , an unconsolidated specialty retail center in Bronx, New York. The sale generated net cash proceeds of $8,863,000 at the Company’s ownership share. In 2015, the Company acquired its partner’s 50% equity ownership interest in three operating apartment communities ( Cherry Tree, Chestnut Lake and Stratford Crossing) in exchange for the Company’s 50% equity ownership in five operating apartment communities ( Eaton Ridge, Newport Landing, Arbor Glen, Parkwood Village and Sutton Landing ) in a non-cash transaction. As a result, the Company recorded gains on disposition of interest in unconsolidated entities as noted above during the year ended December 31, 2015. See Note T – Gain on Change in Control of Interests for detailed information on the gain on change in control of interests related to the three retained operating apartment communities.

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Other Assets The following table summarizes the components of other assets: December 31, 2017 2016 (in thousands) Intangible assets, net $ 106,786 $ 134,562 Prepaid expenses and other deferred costs, net 75,839 73,987 Lease procurement costs, net 59,810 66,065 Total $ 242,435 $ 274,614 During the years ended December 31, 2017, 2016 and 2015 , the Company recorded $21,925,000 , $30,098,000 and $28,019,000 , respectively, of amortization expense related to intangible assets. The following table summarizes the estimated amortization expense related to intangible assets for the next five years: Years Ending December 31, (in thousands) 2018 $ 12,176 2019 11,569 2020 7,763 2021 4,460 2022 3,483

Nonrecourse Mortgage Debt and N

Nonrecourse Mortgage Debt and Notes Payable, Net	12 Months Ended
	Dec. 31, 2017
Nonrecourse Mortgage Debt and Notes Payable, Net [Abstract]
Nonrecourse Mortgage Debt and Notes Payable, Net	Nonrecourse Mortgage Debt and Notes Payable, Net The following tables summarize nonrecourse mortgage debt and notes payable, net, which is collateralized solely by completed rental properties, projects under construction and development and undeveloped land: December 31, 2017 Operating Properties Projects under Construction and Development Total Total Weighted Average Rate (dollars in thousands) Fixed $ 1,615,592 $ 40,165 $ 1,655,757 4.27 % Variable Taxable 680,907 — 680,907 3.59 % Tax-Exempt 648,809 12,888 661,697 2.58 % $ 2,945,308 $ 53,053 $ 2,998,361 3.74 % December 31, 2016 Operating Properties Projects under Construction and Development Total Total Weighted Average Rate (dollars in thousands) Fixed $ 1,874,206 $ 68,855 $ 1,943,061 4.42 % Variable Taxable 508,449 70,222 578,671 2.96 % Tax-Exempt 599,101 — 599,101 1.68 % $ 2,981,756 $ 139,077 $ 3,120,833 3.62 % The following table summarizes the nonrecourse mortgage debt and notes payable, net maturities as of December 31, 2017 : Years Ending December 31, (in thousands) 2018 $ 467,380 2019 480,819 2020 239,281 2021 195,128 2022 208,544 Thereafter 1,438,666 3,029,818 Net unamortized mortgage procurement costs (31,457 ) Total $ 2,998,361

Revolving Credit Facility

Revolving Credit Facility	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Revolving Credit Facility	Revolving Credit Facility In November 2015, the Company entered into a Revolving Credit Agreement which provided for total available borrowings of $500,000,000 (increased to $600,000,000 in May 2016) and contains an accordion provision, subject to bank approval, allowing the Company to increase total available borrowings to $750,000,000 (“Revolving Credit Facility”). The Revolving Credit Facility matures in November 2019, and provides for two six -month extension periods, subject to certain conditions. Borrowings bear interest at the Company’s option at either London Interbank Offered Rate (“LIBOR”) ( 1.56% at December 31, 2017 ) plus a margin of 1.15% - 1.85% ( 1.25% at December 31, 2017 ) or the Prime Rate ( 4.50% at December 31, 2017 ) plus a margin of 0.15% - 0.85% ( 0.25% at December 31, 2017 ). In addition, the Revolving Credit Facility is subject to an annual facility fee of 0.20% - 0.35% ( 0.25% at December 31, 2017 ) of total available borrowings. Up to $150,000,000 of the available borrowings can be used for letters of credit. The applicable margins and annual facility fee are based on the Company’s total leverage ratio (adjusted quarterly, if applicable). The Revolving Credit Facility has restrictive covenants, including a prohibition on certain types of dispositions, mergers, consolidations, and limitations on lines of business the Company is allowed to conduct. Additionally, the Revolving Credit Facility contains financial covenants, including the maintenance of a maximum total leverage ratio, maximum secured and unsecured leverage ratios, maximum secured recourse leverage ratio, a minimum fixed charge coverage ratio, and a minimum unencumbered interest coverage ratio (all as specified in the Revolving Credit Agreement). At December 31, 2017 , the Company was in compliance with all of these financial covenants. The following table summarizes the available credit on the Revolving Credit Facility: December 31, 2017 2016 (in thousands) Total available borrowings $ 600,000 $ 600,000 Less: Outstanding borrowings — — Letters of credit 36,439 44,215 Available credit $ 563,561 $ 555,785 As of December 31, 2017 and 2016 , unamortized debt procurement costs related to the Revolving Credit Facility of $1,798,000 and $2,757,000 , respectively, are included in other assets on the Consolidated Balance Sheets.

Term Loan Facility, Net

Term Loan Facility, Net	12 Months Ended
	Dec. 31, 2017
Term Loan Facility, Net [Abstract]
Long-term Debt [Text Block]	Term Loan Facility, Net In May 2016, the Company entered into a Term Loan Credit Agreement which provides for a $335,000,000 senior unsecured term loan credit facility (“Term Loan Facility”). The Term Loan matures in May 2021 and bears interest at the Company’s option at either LIBOR (based on the approximate date of the initial borrowings and adjusted monthly thereafter) ( 1.36% at December 31, 2017 ) plus a margin of 1.30% - 2.20% ( 1.45% at December 31, 2017 ) or the Prime Rate plus a margin of 0.30% - 1.20% ( 0.45% at December 31, 2017 ). The applicable margins are based on the Company’s total leverage ratio. Upon the Company obtaining an investment grade credit rating, established by certain debt rating agencies for the Company’s long term, senior, unsecured non-credit enhanced debt (the “Debt Ratings”), the applicable margin will, at the Company’s election, be based on the Company’s then-current Debt Ratings. The Term Loan Facility contains identical financial covenants as the Revolving Credit Facility as described in Note G – Revolving Credit Facility . Additionally, the Term Loan Facility contains customary events of default provisions, including failure to pay indebtedness, breaches of covenants and bankruptcy or other insolvency events, which could result in the acceleration of all amounts and cancellation of all commitments outstanding under the Term Loan Facility, as well as customary representations and warranties and affirmative and negative covenants. The following table summarizes the Term Loan Facility, net: December 31, 2017 2016 (in thousands) Total outstanding borrowings $ 335,000 $ 335,000 Net unamortized debt procurement costs (1,332 ) (1,732 ) Total $ 333,668 $ 333,268 Convertible Senior Debt, Net The following table summarizes the convertible senior debt, net: December 31, 2017 2016 (in thousands) 4.250% Notes due 2018 $ 73,215 $ 73,216 3.625% Notes due 2020 40,021 40,021 113,236 113,237 Net unamortized debt procurement costs (599 ) (1,056 ) Total $ 112,637 $ 112,181 All of the senior debt are unsecured senior obligations and rank equally with all existing and future unsecured indebtedness; however, they are effectively subordinated to all existing and future secured indebtedness and other liabilities of the Company’s subsidiaries to the extent of the value of the collateral securing that other debt. During the year ended December 31, 2016, the Company entered into separate, privately negotiated exchange agreements with certain holders of the Company’s convertible senior notes. Under the terms of the agreements, holders agreed to exchange certain notes for either shares of Class A common stock or cash payments. Under the accounting guidance for induced conversions of convertible debt, additional amounts paid to induce the holders to exchange the notes were expensed resulting in a non-tax deductible loss on extinguishment of debt. The following table summarizes the convertible senior debt transactions completed during the year ended December 31, 2016: Agreement Date Issuance Aggregate Principal Class A Common Shares Issued Cash Payments to Noteholders Loss on Extinguishment (in thousands, except share data) January 20, 2016 2016 Senior Notes $ 125 9,298 $ — $ 59 March 14, 2016 2018 Senior Notes 77,310 — 90,958 15,370 March 17, 2016 2018 Senior Notes 4,000 — 4,707 795 March 14, 2016 2020 Senior Notes 76,334 — 86,858 12,823 Total $ 157,769 9,298 $ 182,523 $ 29,047 Convertible Senior Notes due 2018 In July 2011, the Company issued $350,000,000 of 4.250% Convertible Senior Notes due August 15, 2018 (“2018 Senior Notes”) in a private placement. The 2018 Senior Notes were issued at par and accrued interest is payable semi-annually on February 15 and August 15. Holders may convert their 2018 Senior Notes at their option at any time prior to the close of business on the scheduled trading day immediately preceding the maturity date. Initially, upon conversion, a noteholder would have received 46.1425 shares of Class A common stock per $1,000 principal amount of 2018 Senior Notes (“Conversion Rate”), based on a conversion price of approximately $21.67 per share of Class A common stock, subject to adjustment pursuant to the Indenture governing the Notes. The following table summarizes required adjustments to the Conversion Rate and approximate Conversion price of the 2018 Senior Notes triggered by the Company’s cash dividends: Effective Date Conversion Rate Conversion Price (in shares) June 10, 2016 46.6375 $ 21.44 June 9, 2017 47.2567 $ 21.16 December 20, 2017 47.8122 $ 20.92 Convertible Senior Notes due 2020 In July 2013, the Company issued $300,000,000 of 3.625% Convertible Senior Notes due August 15, 2020 (“2020 Senior Notes”) in a private placement. The 2020 Senior Notes were issued at par and accrued interest is payable semi-annually on February 15 and August 15. Holders may convert their 2020 Senior Notes at their option at any time prior to the close of business on the scheduled trading day immediately preceding the maturity date. Initially, upon conversion, a noteholder would have received 41.3129 shares of Class A common stock per $1,000 principal amount of 2020 Senior Notes (“Conversion Rate”), based on a conversion price of approximately $24.21 per share of Class A common stock, subject to adjustment pursuant to the Indenture governing the Notes. The following table summarizes required adjustments to the Conversion Rate and approximate Conversion price of the 2020 Senior Notes triggered by the Company’s cash dividends: Effective Date Conversion Rate Conversion Price (in shares) June 10, 2016 41.7561 $ 23.95 June 9, 2017 42.3105 $ 23.63 December 20, 2017 42.8079 $ 23.36 Consolidated Interest Expense The following table summarizes interest incurred, capitalized and paid on all forms of indebtedness (included in Notes F , G , H and I ): Years Ended December 31, 2017 2016 2015 (in thousands) Interest incurred $ 141,582 $ 170,080 $ 194,041 Interest capitalized (21,151 ) (38,639 ) (36,875 ) Net interest expense from continuing operations $ 120,431 $ 131,441 $ 157,166 Interest incurred from discontinued operations $ — $ 3,540 $ 40,125 Cash paid for interest (net of amount capitalized) $ 116,987 $ 130,766 $ 200,781

Convertible Senior Debt

Convertible Senior Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Convertible Senior Debt	Term Loan Facility, Net In May 2016, the Company entered into a Term Loan Credit Agreement which provides for a $335,000,000 senior unsecured term loan credit facility (“Term Loan Facility”). The Term Loan matures in May 2021 and bears interest at the Company’s option at either LIBOR (based on the approximate date of the initial borrowings and adjusted monthly thereafter) ( 1.36% at December 31, 2017 ) plus a margin of 1.30% - 2.20% ( 1.45% at December 31, 2017 ) or the Prime Rate plus a margin of 0.30% - 1.20% ( 0.45% at December 31, 2017 ). The applicable margins are based on the Company’s total leverage ratio. Upon the Company obtaining an investment grade credit rating, established by certain debt rating agencies for the Company’s long term, senior, unsecured non-credit enhanced debt (the “Debt Ratings”), the applicable margin will, at the Company’s election, be based on the Company’s then-current Debt Ratings. The Term Loan Facility contains identical financial covenants as the Revolving Credit Facility as described in Note G – Revolving Credit Facility . Additionally, the Term Loan Facility contains customary events of default provisions, including failure to pay indebtedness, breaches of covenants and bankruptcy or other insolvency events, which could result in the acceleration of all amounts and cancellation of all commitments outstanding under the Term Loan Facility, as well as customary representations and warranties and affirmative and negative covenants. The following table summarizes the Term Loan Facility, net: December 31, 2017 2016 (in thousands) Total outstanding borrowings $ 335,000 $ 335,000 Net unamortized debt procurement costs (1,332 ) (1,732 ) Total $ 333,668 $ 333,268 Convertible Senior Debt, Net The following table summarizes the convertible senior debt, net: December 31, 2017 2016 (in thousands) 4.250% Notes due 2018 $ 73,215 $ 73,216 3.625% Notes due 2020 40,021 40,021 113,236 113,237 Net unamortized debt procurement costs (599 ) (1,056 ) Total $ 112,637 $ 112,181 All of the senior debt are unsecured senior obligations and rank equally with all existing and future unsecured indebtedness; however, they are effectively subordinated to all existing and future secured indebtedness and other liabilities of the Company’s subsidiaries to the extent of the value of the collateral securing that other debt. During the year ended December 31, 2016, the Company entered into separate, privately negotiated exchange agreements with certain holders of the Company’s convertible senior notes. Under the terms of the agreements, holders agreed to exchange certain notes for either shares of Class A common stock or cash payments. Under the accounting guidance for induced conversions of convertible debt, additional amounts paid to induce the holders to exchange the notes were expensed resulting in a non-tax deductible loss on extinguishment of debt. The following table summarizes the convertible senior debt transactions completed during the year ended December 31, 2016: Agreement Date Issuance Aggregate Principal Class A Common Shares Issued Cash Payments to Noteholders Loss on Extinguishment (in thousands, except share data) January 20, 2016 2016 Senior Notes $ 125 9,298 $ — $ 59 March 14, 2016 2018 Senior Notes 77,310 — 90,958 15,370 March 17, 2016 2018 Senior Notes 4,000 — 4,707 795 March 14, 2016 2020 Senior Notes 76,334 — 86,858 12,823 Total $ 157,769 9,298 $ 182,523 $ 29,047 Convertible Senior Notes due 2018 In July 2011, the Company issued $350,000,000 of 4.250% Convertible Senior Notes due August 15, 2018 (“2018 Senior Notes”) in a private placement. The 2018 Senior Notes were issued at par and accrued interest is payable semi-annually on February 15 and August 15. Holders may convert their 2018 Senior Notes at their option at any time prior to the close of business on the scheduled trading day immediately preceding the maturity date. Initially, upon conversion, a noteholder would have received 46.1425 shares of Class A common stock per $1,000 principal amount of 2018 Senior Notes (“Conversion Rate”), based on a conversion price of approximately $21.67 per share of Class A common stock, subject to adjustment pursuant to the Indenture governing the Notes. The following table summarizes required adjustments to the Conversion Rate and approximate Conversion price of the 2018 Senior Notes triggered by the Company’s cash dividends: Effective Date Conversion Rate Conversion Price (in shares) June 10, 2016 46.6375 $ 21.44 June 9, 2017 47.2567 $ 21.16 December 20, 2017 47.8122 $ 20.92 Convertible Senior Notes due 2020 In July 2013, the Company issued $300,000,000 of 3.625% Convertible Senior Notes due August 15, 2020 (“2020 Senior Notes”) in a private placement. The 2020 Senior Notes were issued at par and accrued interest is payable semi-annually on February 15 and August 15. Holders may convert their 2020 Senior Notes at their option at any time prior to the close of business on the scheduled trading day immediately preceding the maturity date. Initially, upon conversion, a noteholder would have received 41.3129 shares of Class A common stock per $1,000 principal amount of 2020 Senior Notes (“Conversion Rate”), based on a conversion price of approximately $24.21 per share of Class A common stock, subject to adjustment pursuant to the Indenture governing the Notes. The following table summarizes required adjustments to the Conversion Rate and approximate Conversion price of the 2020 Senior Notes triggered by the Company’s cash dividends: Effective Date Conversion Rate Conversion Price (in shares) June 10, 2016 41.7561 $ 23.95 June 9, 2017 42.3105 $ 23.63 December 20, 2017 42.8079 $ 23.36 Consolidated Interest Expense The following table summarizes interest incurred, capitalized and paid on all forms of indebtedness (included in Notes F , G , H and I ): Years Ended December 31, 2017 2016 2015 (in thousands) Interest incurred $ 141,582 $ 170,080 $ 194,041 Interest capitalized (21,151 ) (38,639 ) (36,875 ) Net interest expense from continuing operations $ 120,431 $ 131,441 $ 157,166 Interest incurred from discontinued operations $ — $ 3,540 $ 40,125 Cash paid for interest (net of amount capitalized) $ 116,987 $ 130,766 $ 200,781

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities Risk Management Objective of Using Derivatives The Company maintains an overall interest rate risk management strategy using derivative instruments to minimize significant unplanned impact on earnings and cash flows caused by interest rate volatility. The strategy uses interest rate swaps and caps having indices related to the pricing of specific liabilities. The Company enters into interest rate swaps to convert floating-rate debt to fixed-rate long-term debt, and vice-versa, depending on market conditions. Interest rate swaps are generally for periods of one to ten years. Interest rate caps are generally for periods of one to three years. The use of interest rate caps is consistent with the Company’s risk management objective to reduce or eliminate exposure to variability in future cash flows primarily attributable to increases in interest rates on its floating-rate debt. Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage exposure to interest rate movements. The Company primarily uses interest rate caps and swaps as part of its interest rate risk management strategy. Interest rate caps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an upfront premium. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. The effective portion of changes in the fair value of derivatives designated and qualifying as cash flow hedges is recorded in accumulated OCI and is subsequently reclassified into earnings during the period the hedged forecasted transaction affects earnings. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. Ineffectiveness was insignificant during the years ended December 31, 2017, 2016 and 2015 . During the year ended December 31, 2016, the Company recorded $24,635,000 to the financial statement line item “Interest rate swap breakage fee” on the Consolidated Statement of Operations as an increase to interest expense arising from the early termination of an interest rate swap. The interest rate swap was terminated because the hedged mortgage was paid off during 2016 prior to its 2017 maturity date. As of December 31, 2017 , the Company expects it will reclassify amounts recorded in accumulated OCI into earnings as an increase in interest expense of approximately $3,674,000 within the next twelve months. However, the actual amount reclassified could vary due to future changes in fair value of these derivatives. Fair Value Hedges of Interest Rate Risk The Company enters into total rate of return swaps (“TROR”) on various tax-exempt fixed-rate borrowings. The TROR convert borrowings from a fixed rate to a variable rate. The TROR requires the payment of a variable interest rate, generally equivalent to the Securities Industry and Financial Markets Association (“SIFMA”) rate ( 1.71% at December 31, 2017 ) plus a spread. Additionally, the Company has guaranteed the fair value of the underlying borrowings. Fluctuation in the value of the TROR is offset by the fluctuation in the value of the underlying borrowings, resulting in minimal financial impact. At December 31, 2017 , the aggregate notional amount of TROR designated as fair value hedging instruments is $605,036,000 . The underlying TROR borrowings are subject to a fair value adjustment. Nondesignated Hedges of Interest Rate Risk The Company uses derivative contracts to hedge certain interest rate risk, even though the contracts do not qualify for, or the Company has elected not to apply, hedge accounting. In these situations, the derivative is recorded at its fair value with changes reflected in earnings. The Company has certain undesignated TROR where the associated debt is held by an unconsolidated affiliate or unrelated third parties. The change in fair value of these TROR is recognized in earnings. At December 31, 2017 , the aggregate notional amount of these TROR is $136,746,000 . In instances where the Company enters into separate derivative instruments effectively hedging the same debt for consecutive annual periods, the duplicate amount of notional is excluded from the following disclosure in an effort to provide information that enables the financial statement user to understand the Company’s volume of derivative activity. The following table summarizes the fair values and location in the Consolidated Balance Sheets of all derivative instruments: Fair Value of Derivative Instruments December 31, 2017 Asset Derivatives (included in Other Assets) Liability Derivatives (included in Accounts Payable, Accrued Expenses and Other Liabilities) Current Notional Fair Value Current Notional Fair Value (in thousands) Derivatives Designated as Hedging Instruments Interest rate swaps $ 63,372 $ 1,129 $ 34,078 $ 863 TROR 369,021 3,862 236,015 652 Total $ 432,393 $ 4,991 $ 270,093 $ 1,515 Derivatives Not Designated as Hedging Instruments Interest rate caps $ 69,518 $ — $ — $ — TROR 100,466 4,107 36,280 11,330 Total $ 169,984 $ 4,107 $ 36,280 $ 11,330 December 31, 2016 Derivatives Designated as Hedging Instruments Interest rate swaps $ 64,248 $ 593 $ 34,666 $ 1,504 TROR 235,970 5,008 316,015 12,442 Total $ 300,218 $ 5,601 $ 350,681 $ 13,946 Derivatives Not Designated as Hedging Instruments Interest rate caps $ 69,518 $ — $ — $ — TROR 100,800 4,117 37,044 12,256 Total $ 170,318 $ 4,117 $ 37,044 $ 12,256 The following table summarizes the impact of gains and losses related to derivative instruments designated as cash flow hedges included in the accumulated OCI section of the Consolidated Balance Sheets and in equity in earnings and interest expense in the Consolidated Statements of Operations: Gain (Loss) Reclassified from Accumulated OCI Derivatives Designated as Cash Flow Hedging Instruments Gain (Loss) Recognized in OCI (Effective Portion) Location on Consolidated Statements of Operations Effective Amount Ineffective Amount (in thousands) Year Ended December 31, 2017 Interest rate caps and interest rate swaps $ 476 Interest expense $ (2,801 ) $ (16 ) Earnings from unconsolidated entities (2,568 ) — Total $ 476 $ (5,369 ) $ (16 ) Year Ended December 31, 2016 Interest rate caps and interest rate swaps $ (9,414 ) Interest expense $ (35,008 ) $ 119 Reclassification adjustment for interest rate swap breakage fee (24,635 ) — Net gain (loss) on disposition of full or partial interest in rental properties, net of tax (113 ) — Earnings from unconsolidated entities (3,192 ) — Total $ (9,414 ) $ (62,948 ) $ 119 Year Ended December 31, 2015 Interest rate caps and interest rate swaps $ (12,478 ) Interest expense $ (37,831 ) $ (21 ) Gain on change of control in interests 900 — Earnings from unconsolidated entities (3,721 ) (1 ) Total $ (12,478 ) $ (40,652 ) $ (22 ) The following table summarizes the impact of gains and losses related to derivative instruments not designated as cash flow hedges in the Consolidated Statements of Operations: Net Gain (Loss) Recognized Years Ended December 31, 2017 2016 2015 (in thousands) Derivatives Designated as Fair Value Hedging Instruments TROR (1) $ 10,644 $ (4,624 ) $ 2,794 Derivatives Not Designated as Hedging Instruments Interest rate caps and interest rate swaps $ (45 ) $ (107 ) $ (157 ) TROR 916 (164 ) 5,266 Total $ 871 $ (271 ) $ 5,109 (1) The net gain (loss) recognized in interest expense from the change in fair value of the underlying TROR borrowings was $(10,644) , $4,624 and $(2,794) for the years ended December 31, 2017, 2016 and 2015 , respectively, offsetting the gain (loss) recognized on the TROR. Credit-risk-related Contingent Features The principal credit risk of the Company’s interest rate risk management strategy is the potential inability of a counterparty to cover its obligations. If a counterparty fails to fulfill its obligation, the risk of loss approximates the fair value of the derivative. To mitigate this exposure, the Company generally purchases derivative financial instruments from the financial institution that issues the related debt, from financial institutions with which the Company has other lending relationships, or from financial institutions with a minimum credit rating of BBB+, or its equivalent at the time of the transaction. Agreements with derivative counterparties contain provisions under which the counterparty could terminate the derivative obligations if the Company defaults on its obligations under the Revolving Credit Agreement and designated conditions are fulfilled. In instances where the Company’s subsidiaries have derivative obligations secured by a mortgage, the derivative obligations could be terminated if the indebtedness between the two parties is terminated, either by loan payoff or default of the indebtedness. In addition, certain subsidiaries have agreements containing provisions whereby the subsidiaries must maintain certain minimum financial ratios. As of December 31, 2017 , the Company does not have any derivative contracts containing credit-risk related contingent features, such as a credit rating downgrade, that may trigger collateral to be posted with a counterparty.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company’s financial assets and liabilities subject to fair value measurements are interest rate caps, interest rate swaps, TROR and borrowings subject to TROR (see Note J – Derivative Instruments and Hedging Activities ). Impairment of real estate and unconsolidated entities is also subject to fair value measurements (see Note S – Impairment of Real Estate and Impairment of Unconsolidated Entities and Note Y – Assets and Liabilities Held for Sale and Discontinued Operations ). Fair Value Hierarchy The accounting guidance related to estimating fair value specifies a hierarchy of valuation techniques based upon whether the inputs to those valuation techniques reflect assumptions other market participants would use based upon market data obtained from independent sources (also referred to as observable inputs). The following summarizes the fair value hierarchy: • Level 1 – Quoted prices in active markets that are unadjusted and accessible at the measurement date for identical, unrestricted assets or liabilities; • Level 2 – Quoted prices for identical assets and liabilities in markets that are not active, quoted prices for similar assets and liabilities in active markets or financial instruments for which significant observable inputs are available, either directly or indirectly, such as interest rates and yield curves that are observable at commonly quoted intervals; and • Level 3 – Prices or valuations that require inputs that are unobservable. Inputs used to measure fair value may fall into different levels of the fair value hierarchy. In these cases, the level in the fair value hierarchy is based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. Measurement of Fair Value The Company estimates the fair value of its hedging instruments based on interest rate market and bond pricing models. Although the Company has determined the significant inputs used to value its hedging instruments fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with the Company’s counterparties and its own credit risk utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. As of December 31, 2017 , the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its hedging instruments’ positions and has determined the credit valuation adjustments are not significant to the overall valuation of all of its hedging instruments. As a result, hedging instruments valuations are classified in Level 2. The Company’s TROR have termination values equal to the difference between the fair value of the underlying bonds and the bonds base (acquired) price times the stated par amount of the bonds. Upon termination of the contract with the counterparty, the Company is entitled to receive the termination value if the underlying fair value of the bonds is greater than the base price and is obligated to pay the termination value if the underlying fair value of the bonds is less than the base price. The underlying borrowings generally have call features at par and without prepayment penalties. The call features of the underlying borrowings would result in a significant discount factor to any value attributed to the exchange of cash flows in these contracts by another market participant willing to purchase the Company’s positions. Therefore, the Company believes the termination value of the TROR approximates the fair value another market participant would assign to these contracts. The Company compares estimates of fair value to those provided by the respective counterparties on a quarterly basis. The Company has determined its fair value estimate of TROR is classified in Level 3 of the fair value hierarchy. To determine the fair value of the underlying borrowings subject to TROR, the base price is initially used as the estimate of fair value. The Company adjusts the fair value based upon observable and unobservable measures such as the financial performance of the underlying collateral, interest rate risk spreads for similar transactions and loan to value ratios. In the absence of such evidence, management’s best estimate is used. At December 31, 2017 , the notional amount of TROR borrowings subject to fair value adjustments is approximately $605,036,000 . Items Measured at Fair Value on a Recurring Basis The Company’s financial assets consist of interest rate caps, interest rate swaps and TROR with positive fair values included in other assets. The Company’s financial liabilities consist of interest rate swaps and TROR with negative fair values included in accounts payable, accrued expenses and other liabilities and borrowings subject to TROR included in nonrecourse mortgage debt and notes payable, net. The following table summarizes information about financial assets and liabilities measured at fair value on a recurring basis, and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value: Fair Value Measurements December 31, 2017 Level 1 Level 2 Level 3 Total (in thousands) Interest rate swaps (assets) $ — $ 1,129 $ — $ 1,129 Interest rate swaps (liabilities) — (863 ) — (863 ) TROR (assets) — — 7,969 7,969 TROR (liabilities) — — (11,982 ) (11,982 ) Fair value adjustment to the borrowings subject to TROR — — (3,210 ) (3,210 ) Total $ — $ 266 $ (7,223 ) $ (6,957 ) December 31, 2016 Level 1 Level 2 Level 3 Total (in thousands) Interest rate swap (assets) $ — $ 593 $ — $ 593 Interest rate swaps (liabilities) — (1,504 ) — (1,504 ) TROR (assets) — — 9,125 9,125 TROR (liabilities) — — (24,698 ) (24,698 ) Fair value adjustment to the borrowings subject to TROR — — 7,434 7,434 Total $ — $ (911 ) $ (8,139 ) $ (9,050 ) The following table presents a reconciliation of financial assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3): Net Fair value Total (in thousands) Balance, December 31, 2015 $ (10,785 ) $ 2,810 $ (7,975 ) Total realized and unrealized gains (losses): Included in earnings (4,788 ) 4,624 (164 ) Balance, December 31, 2016 $ (15,573 ) $ 7,434 $ (8,139 ) Total realized and unrealized gains (losses): Included in earnings 11,560 (10,644 ) 916 Balance, December 31, 2017 $ (4,013 ) $ (3,210 ) $ (7,223 ) The following table presents quantitative information about the significant unobservable inputs used to estimate the fair value of financial instruments measured on a recurring basis as of December 31, 2017 : Quantitative Information about Level 3 Fair Value Measurements Fair Value December 31, 2017 Valuation Technique Unobservable Input Input Values (in thousands) TROR $ (4,013 ) Third party bond pricing Bond valuation 98.81 - 118.00 Fair value adjustment to the borrowings subject to TROR $ (3,210 ) Third party bond pricing Bond valuation 98.81 - 101.87 Third party service providers involved in fair value measurements are evaluated for competency and qualifications. Fair value measurements, including unobservable inputs, are evaluated based on current transactions and experience in the real estate and capital markets. The impact of changes in unobservable inputs used to determine the fair market value of the credit valuation adjustment, TROR and fair value adjustment to the borrowings subject to TROR are not deemed to be significant. Fair Value of Other Financial Instruments The carrying amount of accounts receivable and accounts payable, accrued expenses and other liabilities approximates fair value based upon the short-term nature of the instruments. The carrying amount of notes receivable approximates fair value since the interest rates on these notes approximates current market rates for similar instruments when considering the risk profile and quality of the collateral, if applicable. The Company estimates the fair value of its debt instruments by discounting future cash payments at interest rates the Company believes approximate the current market. Estimated fair value is based upon market prices of public debt, available industry financing data, current treasury rates, recent financing transactions, conversion features on convertible senior debt and loan to value ratios. The fair value of the Company’s debt instruments is classified as Level 3 in the fair value hierarchy. The following table summarizes the fair value of nonrecourse mortgage debt and notes payable, net, including balances classified as held for sale (exclusive of the fair value of derivatives), term loan facility, net and convertible senior debt, net: December 31, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Nonrecourse mortgage debt and notes payable, net $ 2,998,361 $ 2,995,559 $ 3,120,833 $ 3,105,587 Term loan facility, net 333,668 333,726 333,268 333,527 Convertible senior debt, net 112,637 130,942 112,181 122,795 Total $ 3,444,666 $ 3,460,227 $ 3,566,282 $ 3,561,909

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company has various guarantees, including indirect guarantees of indebtedness of others. The Company believes the risk of payment under these guarantees, as described below, is remote and, to date, no payments have been made under these guarantees. The Company had outstanding letters of credit of $36,439,000 under the revolving credit facility as of December 31, 2017 , which represents the maximum potential amount of future payments on the letters of credit the Company could be required to make. The Company has entered into certain partnerships whereby the outside investment partner is allocated certain tax credits. These partnerships typically require the Company to indemnify, on an after-tax or “grossed up” basis, the investment partner against the failure to receive or the loss of allocated tax credits and tax losses. At December 31, 2017 , the maximum potential payment under these tax indemnity guarantees was approximately $120,655,000 . The Company believes all remaining requirements for qualifications of tax credits and partnership structures have been and will continue to be met and the Company’s investment partners will be able to receive expense allocations associated with the properties. The Company does not expect to make any remaining payments under these guarantees. The Company’s mortgage loans are nonrecourse; however, in some cases, lenders carve out certain items from the nonrecourse provisions. These carve-out items enable the lenders to seek recourse if the Company or the joint venture engages in certain acts as defined in the respective agreements such as commit fraud, intentionally misapply funds, or intentionally misrepresent facts. The Company has also provided certain environmental guarantees. Under these environmental remediation guarantees, the Company must remediate any hazardous materials brought onto the property in violation of environmental laws. The maximum potential amount of future payments the Company could be required to make on the environmental guarantees is limited to the actual losses suffered or actual remediation costs incurred. A portion of these carve-outs and guarantees have been made on behalf of joint ventures and the Company believes any liability would not exceed its partners’ share of the outstanding principal balance of the loans in which these carve-outs and environmental guarantees have been made. At December 31, 2017 , the outstanding balance of the partners’ share of these loans was approximately $1,493,000,000 . The Company believes the risk of payment on the carve-out guarantees is mitigated, in most cases, by the fact that the Company manages the property, and in the event the Company’s partner violated one of the carve-out items, the Company would seek recovery from its partner for any payments the Company would make. Additionally, the Company further mitigates its exposure through environmental insurance and other types of insurance coverage. The Company monitors its properties for the presence of hazardous or toxic substances. Other than those environmental matters identified during the acquisition of a site (which are generally remediated prior to the commencement of development), the Company is not aware of any environmental liability with respect to its operating properties that would have a material adverse effect on its financial position, cash flows or results of operations. However, there can be no assurance such a material environmental liability does not exist. The existence of any such material environmental liability could have an adverse effect on the Company’s results of operations and cash flow. The Company carries environmental insurance and believes the policy terms, conditions, limits and deductibles are adequate and appropriate under the circumstances, given the relative risk of loss, the cost of such coverage and current industry practice. The Company customarily guarantees lien-free completion of projects under construction. Upon completion, as defined, the guarantees are released. The Company currently provides the following completion guarantees on its completed projects and projects under construction and development (including unconsolidated properties): Total Costs Percent Completed (Unaudited) (dollars in thousands) At December 31, 2017 Openings $ 2,029,900 93 % Under construction 615,800 48 % Total Real Estate $ 2,645,700 82 % In addition to what is stated above, the Company has guaranteed the lender the lien free completion of certain horizontal infrastructure associated with a certain land development project. The maximum amount due by the Company under these completion guarantees is limited to $563,000 . The Company is also involved in certain claims and litigation related to its operations and development. Based on the facts known at this time, management has consulted with legal counsel and is of the opinion that the ultimate outcome of all such claims and litigation will not have a material adverse effect on the financial condition, results of operations or cash flows of the Company. Certain ground leases include provisions requiring the Company to indemnify the ground lessor against claims or damages occurring on or about the leased property during the term of the ground lease. These indemnities generally were entered into prior to the effective date of accounting guidance related to guarantees; therefore, they have not been recorded in the Company’s consolidated financial statements at December 31, 2017 . The maximum potential amount of future payments the Company could be required to make is limited to the actual losses suffered. The Company mitigates its exposure to loss related to these indemnities through insurance coverage. The Company is party to an easement agreement under which it has agreed to indemnify a third party for any claims or damages arising from the use of the easement area in one of its unconsolidated apartment communities. The Company mitigates its exposure to loss related to the easement agreement through insurance coverage. See Note O – Class A Common Units and Related Party Transactions regarding certain tax indemnification payments in connection with a Master Contribution and Sale Agreement entered into during 2006.

Capital Stock

Capital Stock	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Capital Stock	Common Stock - Reclassification Transaction In December 2016, the Company’s Board of Directors approved, and the Company entered into a reclassification agreement with RMS Limited Partnership (“RMS”), the former controlling stockholder of the Company's Class B shares, (the “Reclassification Agreement”). The Reclassification Agreement provided that, at the Effective Time, as defined in the Reclassification Agreement, following the satisfaction of the conditions thereto, each share of Class B Common Stock issued and outstanding immediately prior to the Effective Time would be reclassified and exchanged into 1.31 shares of Class A Common Stock, with a right to cash in lieu of fractional shares (the “Reclassification”). Pursuant to the Reclassification Agreement, the Board of Directors submitted a proposal for stockholder approval to eliminate the dual-class share structure at the Company’s 2017 Annual Meeting of Stockholders. This proposal was approved by the stockholders at the Company’s Annual Meeting of Stockholders on June 9, 2017 and became effective following the market close on June 12, 2017. As a result, each of the 18,788,163 shares of Class B common stock issued and outstanding immediately prior to the Effective Time were reclassified into 1.31 shares of Class A common stock. As such, 24,612,495 additional shares of Class A common stock were issued to the prior Class B common stockholders. Upon completion of this transaction, all outstanding shares of common stock are entitled to one vote per share on all matters brought to the Company’s stockholders, including but not limited to, the election of the entire Board of Directors. Certain professional and consulting fees, including investment banking success fees, incurred directly related to the stock conversion were recorded as a $9,305,000 reduction to additional paid-in capital, in accordance with applicable accounting requirements when raising permanent equity. Amounts include costs paid on behalf of RMS in accordance with the Reimbursement Agreement. See the “Other Related Party Transactions” section of Note O – Class A Common Units and Related Party Transactions for detailed information on the Reimbursement Agreement. Common Stock - REIT Conversion Pursuant to the merger agreement facilitating the Company’s conversion to REIT status, effective as of 11:59 pm, Eastern Time, on December 31, 2015 (the “Effective Time”), each outstanding share of Forest City Enterprises, Inc., the Company’s predecessor, Class A common stock, par value $.33 1/3 per share, and Class B common stock, par value $.33 1/3 per share, automatically converted into one share of Forest City Realty Trust, Inc. Class A common stock, $.01 par value per share, and Class B common stock, $.01 par value per share, respectively. Common Stock - Other Transactions During the years ended December 31, 2016 and 2015, the Company issued shares of Class A common stock in connection with the separate, privately negotiated exchange transactions involving a portion of the Company’s 2016, 2018 and 2020 Senior Notes. See Note I – Convertible Senior Debt, Net for detailed information on these transactions. The Company also received shares of Class A common stock in connection with the termination of a convertible note hedge related to the 2016 Senior Notes. During the years ended December 31, 2017 and 2015, the Company issued shares of Class A common stock to certain BCR entities in exchange of 2006 Units pursuant to the Master Contribution Agreement. See the Note O – Class A Common Units and Related Party Transactions for detailed information on these transactions. In May 2015, the Company issued 37,375,000 shares of Class A common stock in an underwritten public offering at a price of $22.50 per share, which included the underwriters’ exercise of their over-allotment option in full. The offering generated net proceeds of $806,500,000 after deducting underwriting discounts, commissions and other offering expenses. Preferred Stock The Company is authorized to issue shares of preferred stock. Pursuant to the merger agreement facilitating the Company’s conversion to a REIT, at the Effective Time, the par value of the preferred stock was set at $.01 per share. Prior to the Effective Time, the preferred stock of Forest City Enterprises, Inc. (“Series A Preferred stock”) had no par value. As of December 31, 2017 , the Company has no outstanding shares of preferred stock.

Dividends

Dividends	12 Months Ended
	Dec. 31, 2017
Dividends [Abstract]
Dividends [Text Block]	Dividends Prior to the taxable year ended December 31, 2016, our predecessor, Forest City Enterprises, Inc., operated as a C corporation. A REIT is not permitted to retain earnings and profits (“E&P”) accumulated during the periods when the company or its predecessor was taxed as a C corporation or accumulated by the Company’s or its predecessor’s TRS not converted to a qualified REIT subsidiary. The Company was required to make a distribution to its stockholders that equaled or exceeded its accumulated positive E&P. The March 2016 E&P dividend summarized below was based on the estimated cumulative positive E&P of the Company’s predecessor. The following table summarizes cash dividends declared by the Board of Directors on the Company’s common stock (in thousands, except per share data): Type Date Declared Record Date Payment Date Amount Per Share Total Cash Payment 2017 Quarterly November 29, 2017 December 20, 2017 December 29, 2017 $ 0.14 $ 37,344 Quarterly August 22, 2017 September 5, 2017 September 18, 2017 $ 0.14 $ 37,343 Quarterly May 17, 2017 June 9, 2017 June 23, 2017 $ 0.09 $ 23,482 Quarterly March 1, 2017 March 13, 2017 March 27, 2017 $ 0.09 $ 23,441 $ 0.46 $ 121,610 2016 Quarterly November 30, 2016 December 12, 2016 December 23, 2016 $ 0.06 $ 15,620 Quarterly August 18, 2016 September 2, 2016 September 16, 2016 $ 0.06 $ 15,621 Quarterly May 17, 2016 June 10, 2016 June 24, 2016 $ 0.06 $ 15,623 Quarterly February 18, 2016 March 4, 2016 March 18, 2016 $ 0.06 $ 15,596 E&P February 18, 2016 March 4, 2016 March 18, 2016 $ 0.10 $ 25,992 Total $ 0.34 $ 88,452 The following table summarizes the tax treatment of the Company’s Common Stock dividends for the years ended December 31, 2017 and 2016 : December 31, 2017 2016 Amount Per Share % Amount Per Share % Ordinary income $ 0.04 9.44 % $ 0.11 31.49 % Capital gain $ 0.42 90.56 % $ 0.23 68.51 % Total $ 0.46 100.00 % $ 0.34 100.00 %

Class A Common Units and Relate

Class A Common Units and Related Party Transactions	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Class A Common Units and Related Party Transactions	Class A Common Units and Related Party Transactions Master Contribution Agreement and Tax Protection Agreement The Company and certain of its affiliates entered into a Master Contribution and Sale Agreement (the “Master Contribution Agreement”) with Bruce C. Ratner (“Mr. Ratner”), Executive Vice President (through December 31, 2017), and certain entities and individuals affiliated with Mr. Ratner (the “BCR Entities”) in August 2006 to purchase their interests in a total of 30 retail, office and apartment operating properties and service companies in the Greater New York City metropolitan area. The Company issued Class A Common Units (“2006 Units”) in a jointly-owned, limited liability company in exchange for their interests. The 2006 Units may be exchanged for one of the following forms of consideration at the Company’s sole discretion: (i) an equal number of shares of the Company’s Class A common stock or, (ii) cash based on a formula using the average closing price of the Class A common stock at the time of conversion or, (iii) a combination of cash and shares of the Company’s Class A common stock. If the Company elects to pay cash as full or partial consideration in exchange for 2006 Units, the exchanging unit holder(s) may elect to redeem such 2006 Units for an in-kind distribution of one or more properties in lieu of cash, provided certain conditions set forth under the Exchange Rights Agreement adopted pursuant to the Master Contribution Agreement are met. The Company may, in its sole discretion, elect not to proceed with an in-kind redemption if the Company determines in good faith that the Company will suffer any adverse effects from proceeding with the in-kind redemption. The Company has no rights to redeem or repurchase the 2006 Units. Pursuant to the Master Contribution Agreement, certain projects under development would remain owned jointly until each project was completed and achieved “stabilization.” Upon stabilization, each project would be valued and the Company, in its discretion, would choose among various ownership options for the project. As described below, the Company and Mr. Ratner have agreed upon the value of each development project that has reached stabilization. As of December 31, 2017 , air rights for any future residential vertical development at East River Plaza , a specialty retail center in Manhattan, New York, remains the only asset subject to this agreement. The development projects were not covered by the Tax Protection Agreement (the “Tax Protection Agreement”) that the parties entered into in connection with the Master Contribution Agreement. The Tax Protection Agreement indemnified the BCR Entities included in the initial closing against taxes payable by reason of any subsequent sale of certain operating properties and expires in November 2018. Pursuant to the terms of the Master Contribution Agreement, in December 2015, the Company caused certain of its affiliates to acquire the BCR Entities’ interests in Westchester’s Ridge Hill , a regional mall in Yonkers, New York for $10 . Subsequent to the December 2015 transaction, the Company owned 100% of the asset. In January 2016, the Company closed on the disposition of 51% of its equity interest. Pursuant to the terms of the Master Contribution Agreement, in May 2008, the Company caused certain of its affiliates to acquire the BCR Entities’ interests in two stabilized projects, New York Times , an office building in Manhattan, New York, and Twelve MetroTech Center , an office building in Brooklyn, New York. In accordance with the purchase agreements, the applicable BCR Entities assigned and transferred their interests in the two projects to affiliates of the Company and will receive cash of approximately $121,000,000 over a 15 year period. The consideration exchanged by the Company for the BCR Entities’ interest in the two projects was accounted for under the purchase method of accounting. Pursuant to the agreements, the BCR Entities received an initial cash amount of $49,249,000 . The Company calculated the net present value of the remaining payments over the 15 year period using a discounted interest rate. This initial discounted amount of $56,495,000 was recorded and will be accreted up to the total liability through interest expense over the 15 year period using the effective interest method. At December 31, 2017 and 2016 , $3,855,000 and $3,672,000 , respectively, is recorded in accounts payable, accrued expenses and other liabilities related to this obligation. A final payment of $5,000,000 is due in April 2023. As a result of the January 2017 sale of Shops at Bruckner Boulevard , an unconsolidated specialty retail center in Bronx, New York, the Company accrued $482,000 related to a tax indemnity payment due to the BCR Entities in accordance with the terms of the Tax Protection Agreement during the three months ended March 31, 2017, all of which was paid in equal quarterly installments during the year ended December 31, 2017. As a result of the January 2016 sale of 625 Fulton Avenue , a development site in Brooklyn, New York, the Company accrued $6,238,000 related to a tax indemnity payment due to the BCR Entities in accordance with the terms of the Tax Protection Agreement. Installments totaling $4,680,000 were paid during the year ended December 31, 2016. The remaining amount was included in accounts payable, accrued expenses and other liabilities at December 31, 2016 and was paid in January 2017. Class A Common Unit Exchanges At December 31, 2017 and 2016 , 1,111,044 and 1,940,788 of the 2006 Units were outstanding, respectively. The carrying value of the 2006 Units of $56,674,000 and $99,000,000 is included as noncontrolling interests at December 31, 2017 and 2016 , respectively. In August 2017, certain BCR Entities exchanged 686,865 of the 2006 Units. The Company assigned and transferred its ownership interest in 500 Sterling Place , a previously 100% owned apartment community in Brooklyn, New York, for the exchanged 2006 Units. The agreed upon value of the exchanged property was based on an independent third party appraisal and both parties agreed to use $20 as the basis in determining the number of 2006 Units to be exchanged. The Company accounted for the non-cash exchange as a purchase of noncontrolling interests, resulting in a reduction of noncontrolling interests of $35,037,000 , a reduction of completed rental properties, net of $45,044,000 , a reduction of nonrecourse mortgage debt of $34,382,000 and an increase to additional paid-in capital of $22,805,000 , accounting for the agreed upon value of the exchanged property and the difference between the value of consideration exchanged and the historical cost basis of the noncontrolling interest balance. In September 2017, the Company made a $222,000 payment to the BCR entities for the overpayment of estimated closing costs related to the August 2017 exchange transaction. In March 2017, certain BCR Entities exchanged 142,879 of the 2006 Units. The Company issued 142,879 shares of its Class A common stock for the exchanged 2006 Units. The Company accounted for the exchange as a purchase of noncontrolling interests, resulting in a reduction of noncontrolling interests of $7,288,000 , an increase to Class A common stock of $1,000 and a combined increase to additional paid-in capital of $7,287,000 , accounting for the fair value of common stock issued and the difference between the fair value of consideration exchanged and the historical cost basis of the noncontrolling interest balance. In September 2015, certain BCR Entities exchanged 1,032,402 of the 2006 Units. The Company issued 1,032,402 shares of its Class A common stock for the exchanged 2006 Units. The Company accounted for the exchange as a purchase of noncontrolling interests, resulting in a reduction of noncontrolling interests of $52,663,000 , an increase to Class A common stock of $344,000 and a combined increase to additional paid-in capital of $52,319,000 , accounting for the fair value of common stock issued and the difference between the fair value of consideration exchanged and the noncontrolling interest balance. Development Fees During the year ended December 31, 2017, the Company distributed $997,000 to Mr. Ratner, which represented his share of the retainage release of a development fee earned (and accrued by the Company) during 2005 on a fee project for building the Kings County Supreme Court for New York City. The retainage was being held until the final certificate of occupancy was issued. The Company obtained the final certificate of occupancy and collected the retainage during the year ended December 31, 2017, at which time Mr. Ratner’s share was distributed. During 2014, in accordance with the Master Contribution Agreement, the Company accrued and capitalized into the cost basis of the asset an $11,000,000 development fee payable to Mr. Ratner related to Westchester’s Ridge Hill, as certain milestones had been reached in the development and operation of the property. The entire amount was included in accounts payable, accrued expenses and other liabilities at December 31, 2015 and was paid in January 2016. Distribution Preference Payments Pursuant to the Master Contribution Agreement, 2006 Units not exchanged are entitled to a distribution preference payment equal to the dividends paid on an equivalent number of shares of the Company’s common stock. The Company recorded $709,000 and $660,000 during the years ended December 31, 2017 and 2016 , respectively, related to the distribution preference payment, which is classified as noncontrolling interest expense on the Company’s Consolidated Statement of Operations. Other Related Party Transactions In October 2016, the Company entered into a Reimbursement Agreement with RMS (the “Reimbursement Agreement”). The Company agreed to reimburse RMS (together with its officers, directors, employees, beneficiaries, trustees, representatives and agents)(“Reimbursed Persons”) for reasonable and documented fees and out-of-pocket expenses of RMS’s financial, legal and public relations advisors incurred in evaluating and negotiating the Reclassification. In addition, the Company agreed to reimburse the Reimbursed Persons for (i) reasonable costs and expenses incurred in connection with any Proceeding (as defined in the Reimbursement Agreement) to which such Reimbursed Person is a party or otherwise involved in and (ii) any losses, damages or liabilities actually and reasonably suffered or incurred in any such Proceeding by a Reimbursed Person. Amounts incurred subject to the Reimbursement Agreement were approximately $4,060,000 and $1,207,000 during the years ended December 31, 2017 and 2016 , respectively. See Note M - Capital Stock for additional information. During the three months ended September 30, 2017, Charles A. Ratner, the Company’s former Chairman of the Board and brother of James A. Ratner, the Company’s current Chairman of the Board, purchased a life insurance policy from the Company for $826,000 , which represented the book value and net cash surrender value of the policy at the time of the transaction.

Leases

Leases	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Leases	Leases The Company as Lessor The following table summarizes the minimum future rental income to be received on non-cancelable operating leases of commercial properties that generally extend for periods of more than one year: Years Ending December 31, (in thousands) 2018 $ 343,765 2019 320,345 2020 298,282 2021 267,313 2022 247,632 Thereafter 1,129,277 $ 2,606,614 The Company as Lessee The Company is a lessee under various operating leasing arrangements for real property and equipment. The most significant of these involve ground leases which expire between the years 2018 and 2103, excluding optional renewal periods. The Company is subject to participation payments under certain of its ground leases, the most significant of which are in New York City. These payments are triggered by defined events within the respective lease agreements and the timing and future amounts are not determinable by the Company. The following table summarizes the minimum fixed rental payments under long-term leases (over one year) in effect at December 31, 2017 : Years Ending December 31, (in thousands) 2018 $ 9,523 2019 10,899 2020 11,060 2021 11,180 2022 10,769 Thereafter 312,661 $ 366,092 The following table summarizes rent expense: Years Ended December 31, 2017 2016 2015 (in thousands) Rent expense $ 16,659 $ 16,886 $ 14,032

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Company’s 1994 Stock Plan (the “Plan”) permits the award of Class A stock options, restricted shares, performance shares and other equity awards to key employees and nonemployee directors of the Company. The aggregate maximum number of shares that may be issued under the Plan is 21,750,000 for all types of awards. As of December 31, 2017 , the total number of shares available for granting of all types of awards was 5,499,394 . The maximum annual award to an individual is 500,000 of the aggregate stock options and 500,000 of the aggregate restricted shares and performance shares. In addition, the aggregate grant-date fair value of awards granted to a nonemployee director during any calendar year shall not exceed $250,000 . Stock options have a maximum term of 10 years and are awarded with an exercise price at least equal to the market value of the stock on the date of grant. Class A common stock issued upon the exercise of stock options will be issued out of authorized and unissued shares. During the year ended December 31, 2015, Class A common stock issued upon the exercise of stock options was issued out of authorized and unissued shares or treasury stock. The Plan, which is administered by the Compensation Committee of the Board of Directors, does not allow the reduction of option prices without stockholder approval, except for the anti-dilution adjustments. The Company has not amended the terms of any previously issued equity award. All outstanding stock options have an exercise price equal to the fair market value of the underlying stock at the date of grant and a 10 -year term. Stock options and restricted shares have graded vesting over three to four years for employees and one to three years for nonemployee directors. The following table summarizes stock-based compensation costs and related deferred income tax benefit recognized in the financial statements: Years Ended December 31, 2017 2016 2015 (in thousands) Stock option costs $ 590 $ 937 $ 1,314 Restricted stock costs 17,133 14,788 17,211 Performance share costs 9,161 9,738 13,310 Total stock-based compensation costs 26,884 25,463 31,835 Less amount capitalized into qualifying real estate projects (8,146 ) (5,661 ) (7,717 ) Amount charged to operating expenses 18,738 19,802 24,118 Depreciation expense on capitalized stock-based compensation 880 607 894 Total stock-based compensation expense $ 19,618 $ 20,409 $ 25,012 Deferred income tax benefit $ 511 $ 610 $ 9,629 The amount of grant-date fair value expensed immediately for awards granted to retirement-eligible grantees during the years ended December 31, 2017, 2016 and 2015 was $867,000 , $1,166,000 and $1,926,000 , respectively. Stock Options The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions used for options granted during the respective years: Years Ended December 31, 2017 2016 2015 Risk-free interest rate 2.12 % 1.41 % 1.71 % Expected volatility 25.10 % 26.60 % 30.80 % Expected dividend yield 1.69 % 1.04 % 0.00 % Expected term (in years) 5.5 5.5 5.5 The risk-free interest rate was based on published yields of U.S. zero coupon bonds having a maturity date approximating the expected term of the options. Expected volatility was based on the historical volatility of the Company’s stock using the daily closing prices of the Company’s Class A common stock over a period of time equivalent to the expected term of the options. The expected dividend yield was based on the Company’s recent annual dividend divided by the average price of the Company’s Class A common stock during that period. Historical plan experience was used to estimate the expected term of options granted. The following table summarizes stock option activity for the year ended December 31, 2017 : Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in months) Intrinsic Value (in thousands) Outstanding at January 1, 2017 2,545,031 $ 31.25 Granted 26,112 $ 21.83 Exercised (90,545 ) $ 16.54 Forfeited/expired (662,840 ) $ 64.77 Outstanding at December 31, 2017 1,817,758 $ 19.62 42 $ 11,846 Options exercisable (fully vested) at December 31, 2017 1,697,360 $ 19.64 39 $ 11,280 The weighted average grant-date fair value of stock options granted during the years ended December 31, 2017, 2016 and 2015 was $4.79 , $5.00 and $7.79 , respectively. The total intrinsic value of stock options exercised during the years ended December 31, 2017, 2016 and 2015 was $664,000 , $661,000 and $841,000 , respectively. Cash received from stock options exercised during the years ended December 31, 2017, 2016 and 2015 was $1,498,000 , $1,158,000 and $1,488,000 , respectively. There was no income tax benefit realized as a reduction of income taxes payable from stock options exercised during the years ended December 31, 2017, 2016 and 2015 . At December 31, 2017 , there was $84,000 of unrecognized compensation cost related to stock options expected to be recognized over a weighted-average period of 3 months . Restricted Stock The following table summarizes restricted stock activity for the year ended December 31, 2017 : Shares Weighted Average Grant-Date Fair Value Unvested shares at January 1, 2017 1,607,288 $ 21.24 Granted 672,876 $ 21.85 Vested (818,962 ) $ 20.75 Forfeited (75,384 ) $ 21.60 Unvested shares at December 31, 2017 1,385,818 $ 21.80 Restricted stock represents a grant of Class A common stock to key employees and nonemployee directors subject to restrictions on disposition, transferability and risk of forfeiture, while having the rights to vote the shares and receive dividends. Restricted shares subject to the restrictions mentioned above are considered to be nonvested shares under the accounting guidance for share-based payments and are not reflected as issued and outstanding shares until the restrictions lapse. At that time, the shares are released to the grantee and the Company records the issuance of the shares. At December 31, 2017 , all unvested shares of restricted stock were excluded from issued and outstanding shares of Class A common stock in the accompanying consolidated financial statements. The weighted average grant-date fair value of restricted stock granted during the years ended December 31, 2017, 2016 and 2015 was $21.85 , $20.94 and $24.62 , respectively. The total fair value of shares that vested during the years ended December 31, 2017, 2016 and 2015 was $16,993,000 , $17,663,000 and $13,883,000 , respectively. At December 31, 2017 , there was $12,431,000 of unrecognized compensation cost related to restricted stock expected to be recognized over a weighted-average period of 21 months . Performance Shares Performance shares may be granted to selected executives and the vesting of the shares is contingent upon meeting management objectives established by the Compensation Committee of the Board of Directors. The management objectives may be company-wide or business unit performance goals and may include market conditions and service requirements. The performance period may not be less than one year . Performance shares will generally be granted at target levels and the ultimate number of shares earned will depend upon the degree performance goals are met at the end of the performance period. The fair value of performance shares that do not have a market condition are based on the closing price of the underlying stock on the date of grant and recorded as stock-based compensation cost over the requisite service period. If the performance goals are not met or below target, then any related recognized compensation costs will be reversed. If the performance goals are exceeded, additional compensation costs will be recorded, as applicable, up to the maximum specified in the grant. The fair value of performance shares that have a market condition is based on a Monte Carlo simulation and is recorded as stock-based compensation cost over the requisite service period. The cost is recognized even if the market condition is not satisfied, provided the service requirement is met. The weighted average grant-date fair value of performance shares granted during the years ended December 31, 2017, 2016 and 2015 was $24.91 , $17.27 and $32.14 , respectively. All grants have performance goals that include a market condition and the fair values were computed using a Monte Carlo simulation. At December 31, 2017 , there was $4,779,000 of unrecognized compensation costs related to performance shares expected to be recognized over a weighted-average period of 21 months . The following table summarizes performance share activity for the year ended December 31, 2017 : Shares Weighted Average Grant-Date Fair Value Unvested shares at January 1, 2017 1,441,342 $ 23.72 Granted 243,571 $ 24.91 Canceled due to minimum performance goals not being met (286,179 ) $ 17.78 Forfeited (62,040 ) $ 24.95 Unvested shares at December 31, 2017 1,336,694 $ 25.15 As a result of performance achievement versus goals for the performance periods ended December 31, 2017, 776,509 of the unvested performance shares will be canceled and 71,018 shares are expected to vest and be issued as Class A common shares during the three months ended March 31, 2018. The following table summarizes the range of performance shares that can be earned as of December 31, 2017 : Performance Period Range Minimum Shares Target Shares Maximum Shares January 1, 2016 to December 31, 2018 0% to 200% — 253,882 507,764 January 1, 2017 to December 31, 2019 0% to 200% — 235,285 470,570 — 489,167 978,334 In connection with the vesting of restricted stock and performance shares during the years ended December 31, 2017, 2016 and 2015 , the Company repurchased 272,121 shares, 390,703 shares and 222,537 shares, respectively, of Class A common stock to satisfy the employees’ related minimum statutory tax withholding requirements. During the years ended years ended December 31, 2017 and 2016 , shares repurchased were returned to unissued shares with an aggregate cost basis of $6,082,000 and $7,945,000 , respectively. Shares repurchased during the year ended December 31, 2015 were placed in treasury with an aggregate cost basis of $5,543,000 .

Write-Off of Abandoned Developm

Write-Off of Abandoned Development Projects and Demolition Costs	12 Months Ended
	Dec. 31, 2017
Write-off of Abandoned Development Projects and Demolition Costs [Abstract]
Write-Off of Abandoned Development Projects and Demolition Costs [Text Block]	Write-Offs of Abandoned Development Projects and Demolition Costs The Company recorded write-offs of abandoned development projects and demolition costs of $1,596,000 , $10,348,000 and $9,534,000 for the years ended December 31, 2017, 2016 and 2015 , respectively. The Company recorded write-offs of abandoned development projects and demolition costs of unconsolidated entities of $2,107,000 , $327,000 and $10,191,000 during the years ended December 31, 2017, 2016 and 2015 , respectively, which is included in equity in earnings.

Impairment of Real Estate and I

Impairment of Real Estate and Impairment of Unconsolidated Entities	12 Months Ended
	Dec. 31, 2017
Impairment of Real Estate and Impairment of Unconsolidated Entities [Abstract]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Text Block]	Impairment of Real Estate and Impairment of Unconsolidated Entities The impairments recorded during the periods presented represent write-downs to estimated fair value due to a change in events, such as a change in strategy for certain assets, bona fide third-party purchase offers or changes in certain assumptions, including estimated holding periods and current market conditions and the impact of these assumptions to the properties’ estimated future cash flows. The assumptions used to estimate fair value are Level 2 or 3 inputs. Impairment of Real Estate The following table summarizes the Company’s impairment of real estate included in continuing operations: Years Ended December 31, 2017 2016 2015 (in thousands) 461 Dean Street (Apartment) Brooklyn, New York $ 44,288 $ — $ — Regional Malls: Shops at Northfield Stapleton Denver, Colorado — 68,821 — Boulevard Mall Amherst, New York — 52,510 — Shops at Wiregrass Tampa, Florida — 12,464 — Westchester's Ridge Hill Yonkers, New York — — 398,558 Office Buildings: Post Office Plaza Cleveland, Ohio — 11,800 — Illinois Science and Technology Park Skokie, Illinois — 7,900 26,246 Land inventory Las Vegas, Nevada — 1,230 16,307 Other — 2,100 10,323 $ 44,288 $ 156,825 $ 451,434 During the year ended December 31, 2017, the Company began the marketing process of 461 Dean Street . The initiation of the marketing process triggered management to update its undiscounted cash flow analysis, including its probability weighted estimated holding period. As a result, the estimated probability weighted undiscounted cash flows no longer exceeded the carrying value, requiring the Company to adjust the carrying value to its estimated fair value during the year ended December 31, 2017. During the year ended December 31, 2016, the Company’s Board of Directors authorized a process to review strategic alternatives for a portion of the Company’s retail portfolio and had begun discussions with certain strategic partners and other potential buyers for several of its retail assets. In connection with this review, the Company updated its impairment analysis on its retail assets, including increasing the likelihood of near-term sales. As a result, the estimated probability weighted undiscounted cash flows no longer exceeded the carrying value of the Shops at Northfield Stapleton and Boulevard Mall, requiring the Company to adjust the carrying value to their estimated fair value during the year ended December 31, 2016. The Company completed the sale of Shops at Northfield Stapleton in October 2017. The Company executed a deed in lieu transaction with the holder of the nonrecourse mortgage of Boulevard Mall in November 2017. See Note X . Net Gain on Disposition of Full or Partial Interest in Rental Properties, Net of Tax for additional information. The Company decided to pursue the partial sale, through a joint venture, of Shops at Wiregrass and during the first quarter of 2016 negotiations and buyer due diligence were substantially complete and closing of the transaction remained subject to receipt of a third party consent. The advanced status of the transaction at March 31, 2016 triggered management to further update its undiscounted cash flow analysis including its probability weighted estimated holding period. As a result, the estimated probability weighted undiscounted cash flows no longer exceeded the carrying value, requiring the Company to adjust the carrying value to its estimated fair value during the year ended December 31, 2016. The Company received the third party consent and closed on the disposition of 49% of its equity interest in October 2016. During the three months ended September 30, 2016, based on the loss of a potential tenant to fill a significant vacancy, the Company updated its undiscounted cash flow analysis including its probability weighted estimated holding period for Post Office Plaza office building. As a result, the estimated probability weighted undiscounted cash flows no longer exceeded the carrying value, requiring the Company to adjust the carrying value to its estimated fair value during the year ended December 31, 2016. The Company completed the sale of Post Office Plaza in August 2017. During 2015, the Company continued to market all of the operating assets at Illinois Science & Technology Park in Skokie, Illinois and had several interested parties in the assets at pricing that approximated the carrying value of the assets. During the three months ended September 30, 2015, the high bidder withdrew their offer and certain market conditions, including the loss of possible redevelopment incentives, negatively impacted the pricing from other interested parties. At September 30, 2015, discussions with a potential purchaser were ongoing and remained subject to further negotiation. Based on these factors, the Company increased the likelihood of a near-term sale and reduced the pricing in such scenario in its estimated probability weighted undiscounted cash flows. As a result, these estimated undiscounted cash flows no longer exceed the carrying value of the assets, requiring the Company to adjust the carrying value to its estimated fair value during the year ended December 31, 2015. During the three months ended December 31, 2015, discussions with the potential buyer ceased, as mutually agreeable terms could not be reached. During the year ended December 31, 2016, the Company received a letter of intent for the operating assets at Illinois Science & Technology Park . Based on the letter of intent pricing, the Company updated its undiscounted cash flow analysis resulting in the estimated undiscounted cash flows no longer exceeding the carrying value of the assets, requiring the Company to adjust the carrying value to its estimated fair value during the year ended December 31, 2016. The Company completed the sale of Illinois Science & Technology Park in January 2017. During 2015, the Company owned 13.5 acres of land located in Las Vegas, Nevada, which was included in land inventory on its Consolidated Balance Sheets. The Company had been marketing the land for sale for over twelve months without closing a sale of any of the parcels. During the year ended December 31, 2015, it became evident the expected sale price was less than originally estimated and lower than its carrying value. At September 30, 2015, the Company had a letter of intent for a portion of the land and continued to market the remaining parcels. Using the letter of intent pricing, in addition to other information gathered from other market participants, including verbal bids, the Company adjusted its estimated selling price, less cost to sell, to its estimated fair value during the year ended December 31, 2015. During the three months ended December 31, 2015, the Company sold 6.1 acres of the land at amounts that approximated the carrying value. During the year ended December 31, 2016, the Company signed a purchase and sale agreement for the remaining parcels. As a result, the Company adjusted its estimated selling price, less costs to sell, to its estimated fair value during the year ended December 31, 2016. During the year ended December 31, 2015, the Company decided to pursue the partial sale, through a joint venture, of Westchester's Ridge Hill . At September 30, 2015, discussions with a potential joint venture partner were ongoing and remained subject to further negotiation and applicable due diligence periods. The advanced status of the discussions triggered management to update its undiscounted cash flow analysis including its probability weighted estimated holding period. As a result, the estimated probability weighted undiscounted cash flows no longer exceeded the carrying value, requiring the Company to adjust the carrying value to its estimated fair value during the year ended December 31, 2015. The Company closed on the disposition of 51% of its equity interest in January 2016, at which time the property was deconsolidated and accounted for on the equity method subsequent to the partial disposition transaction. Impairment of Unconsolidated Entities The following table summarizes the Company’s impairment of unconsolidated entities: Years Ended December 31, 2017 2016 2015 (in thousands) Westchester’s Ridge Hill Yonkers, New York $ 10,600 $ — $ — Pacific Park Brooklyn Brooklyn, New York $ — $ 299,300 $ — Federally assisted housing apartment communities Various — — 10,295 Other — 7,100 3,549 $ 10,600 $ 306,400 $ 13,844 During the year ended December 31, 2017, the Company signed a definitive agreement for the sale of its remaining 49% equity interest of Westchester’s Ridge Hill , a regional mall in Yonkers, New York, to its partner. This triggered management to update its impairment analysis, including its estimated selling price. As a result, the estimated fair value no longer exceeded the carrying value, requiring the Company to adjust the carrying value to its estimated fair value during the year ended December 31, 2017. Pacific Park Brooklyn is a 22 acre mixed-use project in Brooklyn, New York. On June 30, 2014, the Company entered into a joint venture with Greenland Atlantic Yards, LLC, a subsidiary of Shanghai-based Greenland Holding Group Company Limited (“Greenland”), to develop the project. Under the joint venture, Greenland acquired 70% of the project and agreed to co-develop the project with the Company, along with sharing in the entire project costs going forward in proportion to ownership interests. The joint venture was formed to execute on the remaining development rights, including the infrastructure and vertical construction of the apartment units, but excluded Barclays Center and 461 Dean Street apartment community. Consistent with the approved master plan, the joint venture agreed to develop the remaining portion of Phase I and all of Phase II of the project, including the permanent rail yard. At the time of closing, the remaining portion of Phase I included seven buildings, totaling approximately 3.1 million square feet. Phase II consists of seven buildings totaling approximately 3.3 million square feet and further obligations to complete significant additional infrastructure improvements including a platform over the permanent rail yard. Upon closing of the partial sale on June 30, 2014, it was determined the Company was not the primary beneficiary of the joint venture and the entity was deconsolidated and subsequently accounted for under the equity method of accounting. The transaction resulted in net cash proceeds of $208,275,000 . The basis of the investment at the time approximated fair value as supported by the sales price and underlying discounted cash flow model used by both parties to underwrite the transaction. Due to the nature of the project in terms of size, duration and complexity, the underlying discounted cash flow model included many estimates and assumptions of future events. Key estimates in the discounted cash flow model include horizontal infrastructure costs including, among other things, estimates of completing the permanent rail yard and the platform over the rail yard, rent growth in the rental buildings and sales prices for condominium buildings, trade costs for vertical construction, timing of starting vertical construction and opening buildings, terminal cap rates and the underlying discount rate. The joint venture broke ground on the first affordable apartment community, 535 Carlton , in December, 2014. In mid-2015, the joint venture commenced construction on two more buildings, 38 Sixth Avenue , an affordable apartment building, and 550 Vanderbilt, a condominium building. From the formation of the joint venture in June 2014 through the quarter ended June 30, 2016, the Company reviewed the estimates and assumptions in the discounted cash flow model and updated them as necessary. During the three months ended September 30, 2016, it became evident the occupancy and rental rate declines in the Brooklyn market were not temporary as a result of an increased supply of new rental product amplified by the sun-setting and the uncertainty around the 421 A real estate tax abatement program. Also, the condominium market in New York has softened, causing the projected sale schedule for 550 Vanderbilt to be adjusted accordingly. Separately, the construction costs across the New York market continued to trend upward, resulting in increases in the estimated trade costs for certain infrastructure as well as vertical construction. As a result, during the three months ended September 30, 2016, as part of the Company’s formal strategic plan update, a decision was made to revise the overall project schedule for Pacific Park Brooklyn . Accordingly, the Company updated the discounted cash flow model to reflect the updated timing of the project schedule as well as the revenue, expense and cost assumptions. Based on the above, the estimated fair value of the investment no longer exceeded the carrying value, requiring the Company to adjust the carrying value to its estimated fair value. As part of the Company’s strategy to focus on core products in core markets, the Company executed a master purchase and sale agreement for the sale of 47 (including 44 unconsolidated investments and 3 consolidated properties) federally assisted housing apartment communities in January 2016. Based on the pricing established during the negotiations, the Company updated its impairment calculations. As a result, the Company recorded an other-than-temporary impairment of $10,295,000 in the year ended December 31, 2015 related to six of these unconsolidated investments. Impairment - Fair Value Information The following table presents quantitative information about the significant unobservable inputs used to determine the fair value of the impairment of real estate and unconsolidated investments for the years ended December 31, 2017, 2016 and 2015 : Quantitative Information about Level 3 Fair Value Measurements Fair Value Valuation Technique Unobservable Input Range of Input Values (in thousands) December 31, 2017 Impairment of real estate $ 152,575 Indicative bid Indicative bid N/A (1) Impairment of unconsolidated investments $ 225,890 Indicative bid Indicative bid N/A (1) December 31, 2016 Impairment of real estate $ 371,139 Indicative bids Indicative bids N/A (1) Impairment of real estate $ 18,500 Comparable property market analysis Price per square foot $39 per square foot Impairment of unconsolidated investments $ — Discounted cash flows Discount rate 9.8% Market capitalization rate 3.9% - 6.0% Impairment of unconsolidated investments $ 3,600 Indicative bids Indicative bids N/A (1) December 31, 2015 Impairment of real estate $ 615,797 Indicative bids Indicative bids N/A (1) Impairment of real estate $ 5,128 Comparable property market analysis Price per square foot $18 per square foot Impairment of unconsolidated investments $ 8,847 Indicative bids Indicative bids N/A (1) (1) These fair value measurements were derived from bona fide purchase offers from third party prospective buyers, subject to the Company’s corroboration for reasonableness.

Net Gain (Loss) on Disposition

Net Gain (Loss) on Disposition of Full or Partial Interest in Development Projects, Net of Tax	12 Months Ended
	Dec. 31, 2017
Net Gain (Loss) on Disposition of Full or Partial Interest in Development Projects, Net of Tax [Abstract]
Net Gain (Loss) on Disposition of Full or Partial Interest in Development Projects, Net of Tax	Net Gain (Loss) on Disposition of Full or Partial Interest in Development Projects, Net of Tax In January 2016, the Company completed the sale of 625 Fulton Avenue , a development site in Brooklyn, New York. The transaction resulted in net cash proceeds of $151,776,000 . The Company recorded a net pre-tax gain on disposition of full interest in development projects of $136,687,000 during the year ended December 31, 2016.

Net Gain on Disposition of Full

Net Gain on Disposition of Full or Partial Interest in Rental Properties, Net of Tax	12 Months Ended
	Dec. 31, 2017
Net Gain (Loss) on Disposition of Full or Partial Interest in Rental Properties, Net of Tax [Abstract]
Net Gain on Disposition of Full or Partial Interests in Rental Properties, Net of Tax	Net Gain on Disposition of Full or Partial Interest in Rental Properties, Net of Tax The following table summarizes the net gain (loss) on disposition of full or partial interest in rental properties, net of tax: Years Ended December 31, 2017 2016 2015 (in thousands) Retail Centers: Fairmont Cinema San Jose, California $ 4,128 $ — $ — QIC Transactions Various 2,197 21 — Avenue at Tower City Center & Tower City Parking Cleveland, Ohio 500 14,207 — Office Buildings: Illinois Science and Technology Park (4 buildings) Skokie, Illinois 3,771 — — Post Office Plaza Cleveland, Ohio (1,244 ) — — Terminal Tower Cleveland, Ohio — 14,391 — Aperture Center Albuquerque, New Mexico — (171 ) — Skylight Office Tower Cleveland, Ohio — — 1,746 Federally assisted housing apartments Various 2,693 — — Grand Lowry Lofts (Apartment Community) Denver, Colorado — 2,333 — Military Housing Various — 141,675 — Johns Hopkins Parking Garage Baltimore, Maryland — (623 ) — Other 6,947 664 — 18,992 172,497 1,746 Income tax effect (192 ) (51,213 ) (679 ) 18,800 121,284 1,067 Deed-in-lieu transaction: Boulevard Mall Amherst, New York 29,845 — — $ 48,645 $ 121,284 $ 1,067 The 2016 income tax effect on the net gain on disposition of full or partial interest in rental properties, net of tax primarily relates to the deferred taxes recognized upon the partial disposition of Westchester’s Ridge Hill, a formerly wholly owned regional mall in Yonkers, New York, and the disposal of military housing entities, as these assets were held by our TRS and remained subject to federal income tax. Military Housing During the year ended December 31, 2016, the Company completed the sale of its interests in entities that develop and manage military family housing. The sale generated net cash proceeds of $208,305,000 . These entities were primarily service providers generating fee revenue. The primary assets acquired by the buyer were intangible assets of approximately $29,000,000 and investments in unconsolidated entities, net, of approximately $14,600,000 . Terminal Tower During the year ended December 31, 2016, the Company completed the sale of Terminal Tower , an office building in Cleveland, Ohio. The Company’s corporate headquarters is located in the Terminal Tower and the Company has evaluated options and will relocate its headquarters in downtown Cleveland, Ohio. In connection with the sale, the Company entered into an 18 month lease agreement, (minimum initial term) with various options to extend up to 48 months, to provide the Company the necessary time to evaluate and relocate its corporate headquarters. While the Company transferred all risks and rewards of ownership of the property to the buyer, the Company’s expected estimated lease term resulted in more than a minor, but less than substantially all of the use of the asset through the leaseback transaction. As a result, the Company deferred $7,917,000 of the gain which will be amortized as an offset to rent expense over the lease term, and recorded a net gain on disposition of $14,391,000 . The sale generated net cash proceeds of $38,027,000 . QIC Transactions The Shops at Northfield Stapleton During the year ended December 31, 2017, in connection with the decision to dispose of substantially all the Company’s regional mall assets to QIC, the Company completed the sale of Shops at Northfield at Stapleton in Denver, Colorado. This was the first of the 10 regional mall assets to be sold to QIC. The disposition, which resulted in the full recognition of the gain, generated net cash proceeds of $50,019,000 and a note receivable of $36,935,000 which bears interest at 4.25% per annum payable monthly and matures in 2019. Westchester’s Ridge Hill During the year ended December 31, 2016, the Company entered into a joint venture agreement with outside partners, affiliated entities of QIC, one of the largest institutional investment managers in Australia. The outside partner invested in and received 51% of our equity interests in Westchester’s Ridge Hill. The Company received net cash proceeds of $75,448,000 along with the buyer assuming debt of $169,369,000 , representing 51% of the nonrecourse mortgage debt of the property. Based on the amount of cash received, the outside partner’s minimum initial investment requirement was met and the transaction qualified for full gain recognition related to the partial sale. The property is adequately capitalized and does not contain the characteristics of a VIE. Based on the substantive participating rights in all significant decision making areas held by the outside partner with regards to the joint venture, the Company concluded it appropriate to deconsolidate the entity and account for it under the equity method of accounting. Ballston Quarter During the year ended December 31, 2016, the Company formed and entered into a new joint venture with outside partners, affiliated entities of QIC. The Company contributed its equity interest in Ballston Quarter , a formerly wholly owned regional mall in Arlington, Virginia, and certain residential development rights to the new joint venture. The outside partner invested $36,269,000 of cash directly into the new joint venture and assumed debt of $20,825,000 , representing 49% of the nonrecourse mortgage debt of the property. The transaction does not meet the requirements to be recognized as a sale for accounting purposes as the Company formed and entered into a new joint venture and has a commitment to re-invest its entire cash proceeds received from the sale as a part of a major redevelopment plan of the asset. Upon closing, the entity was deemed to have insufficient equity and was assessed for consolidation purposes using the VIE model. Based on this and the substantive participating rights in all significant decision making areas of the outside partner, the Company concluded it appropriate to deconsolidate the entity and account for its interest under the equity method of accounting at historical cost. Shops at Wiregrass During the year ended December 31, 2016, the Company entered into a new joint venture agreement with outside partners, affiliated entities of QIC. The outside partner invested in and received 49% of our equity interests in Shops at Wiregrass , a formerly wholly owned regional mall in Tampa, Florida and a development opportunity adjacent to the Shops at Wiregrass . The Company received net cash proceeds of $24,906,000 along with the buyer assuming debt of $40,497,000 , representing 49% of the nonrecourse mortgage debt of the property. Based on the amount of cash received, the outside partner’s minimum initial investment requirement was met and the transaction qualified for full gain recognition related to the partial sale. The property includes a development opportunity that is deemed to have insufficient equity and was assessed for consolidation purposes using the VIE model. Based on this and the substantive participating rights in all significant decision making areas held by the outside partner with regards to the joint venture, the Company concluded it appropriate to deconsolidate the entity and account for it under the equity method of accounting. Boulevard Mall During the year ended December 31, 2017, the Company executed a deed-in-lieu transaction with the Special Servicer who held the nonrecourse mortgage on the property and recorded a gain on disposition of rental property in deed-in-lieu transaction.

Gain on Change in Control of In

Gain on Change in Control of Interests	12 Months Ended
	Dec. 31, 2017
Gain on Change in Control of Interests [Abstract]
Gain on Change in Control of Interests	Gain on Change in Control of Interests The following table summarizes the gain on change in control of interests: Years Ended December 31, 2017 2016 2015 (in thousands) University Park at MIT Cambridge, Massachusetts $ — $ — $ 463,643 Apartment Communities: Cherry Tree Strongsville, Ohio — — 7,391 Chestnut Lake Strongsville, Ohio — — 8,525 Stratford Crossing Wadsworth, Ohio — — 8,125 Other — — (1,405 ) $ — $ — $ 486,279 Apartment Communities In April 2015, the Company acquired its partner’s 50% equity ownership interest in three operating apartment communities ( Cherry Tree, Chestnut Lake and Stratford Crossing) in exchange for the Company’s 50% equity ownership in five operating apartment communities ( Arbor Glen, Eaton Ridge, Newport Landing, Parkwood Village and Sutton Landing ) in a non-cash transaction. Subsequent to the transaction, the Company owns 100% of the three retained operating apartment communities. See Note D – Investments in Unconsolidated Entities for detailed information on the net gain on disposition of interest in unconsolidated entities related to the five operating apartment communities exchanged. University Park at MIT In June 2015, the Company completed the share purchase and redemption agreement with its partner to acquire the partner’s 49% equity ownership interest in seven life science office properties and two parking facilities at University Park at MIT , a mixed-use life science office campus in Cambridge, Massachusetts (“MIT Assets”) . The Company used $386,156,000 of the net proceeds from the May 2015 equity offering to finance this acquisition. See Note M – Capital Stock for information on the equity offering. Prior to the acquisition, the Company owned 51% and had accounted for the MIT Assets using the equity method of accounting. Subsequent to the transaction, the Company owns 100% of these assets and has concluded it appropriate to consolidate the assets. As a result, the Company remeasured its equity interests, as required by the accounting guidance, at fair value (based upon the income approach using current rents and market cap rates and discount rates) and recorded a gain on change in control of interests as noted above. The fair value of the acquisition was allocated as follows. All amounts are presented in thousands. Real Estate, net $ 1,121,786 Restricted cash 17,235 Notes and accounts receivable, net 1,801 Other assets (1) 103,804 1,244,626 Mortgage debt and notes payable, nonrecourse (363,147 ) Accounts payable, accrued expenses and other liabilities (2) (94,214 ) Net assets acquired $ 787,265 Gain on change in control of interests $ 463,643 Carrying value of previously held equity interests (62,534 ) Fair value of previously held equity interests (3) 401,109 Cash paid 386,156 Total $ 787,265 (1) Primarily consists of $78,000 of in-place leases and $20,000 of below-market ground leases with weighted-average lives at the time of acquisition of 3.6 years and 60 years , respectively. (2) Primarily consists of $49,000 of below-market tenant leases and $24,000 of above-market ground leases with weighted-average lives at the time of acquisition of 3.6 years and 58 years , respectively. (3) The significant assumptions used to value the previously held equity interests in the MIT Assets were determined to be Level 3 inputs. The weighted-average discount rate applied to cash flows and the weighted-average terminal capitalization rate were 7.0% and 6.0% , respectively. Pro Forma Information The following unaudited supplemental pro forma operating data is presented for the year ended December 31, 2015, as if the step acquisition related to the MIT Assets was effective on January 1, 2014. The gain on change in control of interest related to this acquisition was adjusted to the assumed acquisition date. The unaudited supplemental pro forma operating data is not necessarily indicative of what the Company’s actual results of operations would have been assuming the transactions had been effective as set forth above, nor do they purport to represent the Company’s results of operations for future periods. The qualitative and quantitative effect to the pro forma operating data related to the remaining acquisitions described in the table above was not material. Pro Forma Adjustments As Reported Year Ended December 31, 2015 Remove: Gain on Change in Control of Interests (1) Pro Forma Adjustments (2) Pro Forma Year Ended December 31, 2015 (in thousands, except per share data) Revenues $ 978,231 $ — $ 43,742 $ 1,021,973 Earnings from continuing operations $ 544,810 $ (283,828 ) $ (15,211 ) $ 245,771 Net earnings attributable to common stockholders $ 496,042 $ (283,828 ) $ (15,211 ) $ 197,003 Weighted average shares outstanding - Basic 237,559,598 237,559,598 Net earnings attributable to common stockholders - Basic $ 2.05 $ 0.81 Weighted average shares outstanding - Diluted 250,848,286 250,848,286 Net earnings attributable to common stockholders - Diluted $ 1.97 $ 0.80 (1) Gain on change in control of interests related to MIT Assets of $463,643 , net of tax of $179,815 . (2) Represents additional depreciation and amortization expense related to the increased basis of real estate and intangible assets, plus pro forma earnings of the current ownership interests, less actual equity in earnings related to the Company’s prior ownership for the periods presented.

Gain (Loss) on Extinguishment o

Gain (Loss) on Extinguishment of Debt	12 Months Ended
	Dec. 31, 2017
Gain (Loss) on Extinguishment of Debt [Abstract]
Gain (Loss) on Extinguishment of Debt	Loss on Extinguishment of Debt For the years ended December 31, 2017, 2016 and 2015 , the Company recorded $(2,961,000) , $(32,960,000) and $(65,086,000) , respectively, as loss on extinguishment of debt . The loss on extinguishment of debt recorded for 2017 primarily relates to a loss on extinguishment of nonrecourse mortgage debt at Illinois Science and Technology Park , office buildings in Skokie, Illinois that were sold during the three months ended March 31, 2017. The loss o n extinguishment of debt recorded for 2016 primarily relates to the January and March 2016 separate, privately negotiated exchange transactions involving a portion of the Company’s 2016, 2018 and 2020 Senior Notes. See Note I – Convertible Senior Debt, Net for detailed information on the non-tax deductible loss on extinguishment of debt. The loss on extinguishment of debt recorded for 2015 primarily relates to the February, March and July 2015 separate, privately negotiated exchange transactions involving a portion of the Company’s 2016, 2018 and 2020 Senior Notes.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the years ended December 31, 2015 and prior, the Company filed a consolidated United States federal income tax return, which included all of its wholly owned subsidiaries. For the taxable year ended December 31, 2016, the Company filed as a REIT and the Company’s TRSs filed as C corporations. The Company files combined income tax returns in various states and files individual separate income tax returns in other states. During 2015, the Company completed the necessary preparatory work, receipt of necessary third party consents and necessary approvals, including stockholder approvals, such that the Company believes it has been organized and operates in a manner that enables it to qualify, and intends to operate in a manner that will allow it to continue to qualify, as a REIT for federal income tax purposes. As a result, the income tax provision for the year ended December 31, 2015 includes a $588,607,000 deferred tax benefit from de-recognizing the deferred tax assets and liabilities associated with the entities included in the REIT and adjusting the valuation allowance required on the TRS deferred tax assets. As a REIT, the Company will generally be allowed a deduction for dividends it pays, and therefore, will not be subject to United States federal corporate income tax on its taxable income currently distributed to stockholders. The Company may be subject to certain state gross income and franchise taxes, as well as taxes on any undistributed income and federal and state corporate taxes on any income earned by its TRSs. In addition, the Company could be subject to corporate income taxes related to assets held by the REIT which are sold during the 5 year period following the date of conversion (ending December 31, 2020), to the extent sold assets had a built-in gain on the date of conversion. The following table reconciles REIT earnings (loss), before income taxes to the Company’s REIT taxable earnings: Year Ended December 31, 2017 December 31, 2016 (in thousands) Earnings (loss) before income taxes $ 144,890 $ (454,173 ) Net gain (loss) on disposition of full or partial interest in development projects (113 ) 136,687 Net gain on disposition of full or partial interest in rental properties 18,992 172,497 Gain on disposition of rental property in deed-in-lieu transaction 29,845 — Less: Noncontrolling interests (9,006 ) (6,078 ) Net earnings (loss) before income taxes 184,608 (151,067 ) Less: TRS earnings (loss) 9,399 (117,074 ) Less: SubREITs loss (390 ) (3,072 ) Less: Stand-alone TRSs & other earnings (loss) 1,281 (789 ) REIT earnings (loss) before income taxes $ 174,318 $ (30,132 ) Book to Tax Adjustments: Costs on land and rental properties under development expensed for tax purposes (4,991 ) (5,286 ) Impairment of real estate and land held for divestiture 10,600 160,595 Book gain on sales in excess of tax gain (14,588 ) (73,329 ) Excess of tax over financial statement depreciation and amortization 42,576 77,725 Revenues and expenses recognized in different periods for book and tax 11,170 (28,882 ) Other tax adjustments 4,188 4,540 Stock based compensation - compensation and depreciation limitations 19,376 20,122 Stock option exercises (18,114 ) (23,958 ) Conversion/exchange of senior debt — 26,895 Tax deductible restricted stock dividend (684 ) (592 ) REIT taxable earnings $ 223,851 $ 127,698 The following table summarizes the income tax expense (benefit) related to continuing operations before gains (loss) on disposal of real estate: Years Ended December 31, 2017 2016 2015 (in thousands) Current Federal $ 426 $ 335 $ 1,626 State 6,160 2,905 513 6,586 3,240 2,139 Deferred Federal (28,200 ) (310 ) (480,025 ) State — 803 (103,892 ) (28,200 ) 493 (583,917 ) Total income tax expense (benefit) $ (21,614 ) $ 3,733 $ (581,778 ) The effective tax rate for income taxes from continuing operations varies from the federal statutory rate of 35% due to the following items: Years Ended December 31, 2017 2016 2015 (dollars in thousands) Earnings (loss) before income taxes and earnings from unconsolidated entities $ 20,106 $ (190,640 ) $ (66,797 ) Equity in earnings of unconsolidated entities, net of impairment 124,784 (263,533 ) 28,762 Net gain (loss) on disposition of full or partial interest in development projects (113 ) 136,687 — Net gain on disposition of full or partial interest in rental properties 18,992 172,497 1,746 Gain on disposition of rental property in deed-in-lieu transaction 29,845 — — Less: Noncontrolling interests (9,006 ) (6,078 ) (13,258 ) Net earnings (loss) before income taxes 184,608 (151,067 ) (49,547 ) Less: REIT earnings (loss) 174,318 (30,132 ) — Less: SubREIT, Stand-alone TRS and other earnings (loss) 891 (3,861 ) — TRS income (loss) before income taxes 9,399 (117,074 ) (49,547 ) Income taxes computed at the statutory rate 3,290 (40,976 ) (17,341 ) Increase (decrease) in income tax resulting from: State taxes, net of federal benefit 1,137 (18,492 ) 2,207 State net operating loss, net of federal benefit 5,148 (7,586 ) 1,544 General business credits (243 ) 121 (307 ) Valuation allowance (1) (110,575 ) 127,726 (912 ) Charitable contributions (66 ) 151 1,127 Permanent adjustments (1,799 ) (1,520 ) 668 Conversion/Exchange of senior debt — — 20,501 Deferred tax adjustment due to REIT conversion — — (688,233 ) Valuation allowance adjustment due to REIT conversion — — 99,626 State tax rate change (2,128 ) — — Effects of federal tax law change (1) 70,676 — — Asset transfers into TRS 33,735 — — Other 125 (5,704 ) 21 Total income tax expense (benefit) $ (700 ) $ 53,720 $ (581,099 ) Effective tax rate (7.45 )% (45.89 )% 1,172.82 % The components of the deferred income tax expense (benefit) for continuing operations are as follows: Excess of tax over financial statement depreciation and amortization $ 1,612 $ 2,509 $ 2,097 Costs on land and rental properties under development expensed for tax purposes 7,121 211 13,520 Revenues and expenses recognized in different periods for tax and financial statement purposes (26,046 ) 112,205 174,072 Difference between tax and financial statements related to unconsolidated entities 33,143 (104,950 ) (24,474 ) Impairment of real estate and land held for divestiture (15,501 ) (1,165 ) (158,002 ) Deferred state taxes, net of federal benefit 5,350 (25,677 ) 2,893 Utilization of (addition to) tax loss carryforward excluding effect of stock options 34,387 (55,231 ) (8,566 ) Valuation allowance (110,575 ) 127,726 (912 ) General business credits 4 121 (307 ) Deferred tax adjustment due to REIT conversion — — (688,233 ) Valuation allowance adjustment due to REIT conversion — — 99,626 Deferred effect of state rate change (2,128 ) — — Effect of federal tax law change (2) 42,576 — — Alternative Minimum Tax credits 1,857 (1,857 ) — Deferred income tax expense (benefit) $ (28,200 ) $ 53,892 $ (588,286 ) (1) Includes the effect in the TRS of the 2017 federal tax rate change under the new tax law from 35% to 21% effective for years ending December 31, 2018 and beyond. (2) Includes the effect in the REIT and TRS of the 2017 federal tax rate change from 35% to 21% , and a $25,600 and $2,500 deferred tax benefit recorded for the REIT and the TRS, respectively, to record the AMT credit receivable as discussed below. The following table summarizes the components of the deferred income tax asset/(liability): Temporary Differences Deferred Tax December 31, 2017 December 31, 2016 December 31, 2017 December 31, 2016 (in thousands) Depreciation $ (9,843 ) $ (10,319 ) $ (2,869 ) $ (4,257 ) Capitalized costs 254,046 237,299 74,054 97,886 Tax loss carryforward 106,505 204,752 22,366 71,663 State loss carryforward, net of federal benefit — — 9,198 12,717 Valuation allowance — — (169,600 ) (280,175 ) Federal tax credits and other carryforwards — — 232 2,632 Basis in unconsolidated entities 265,071 301,850 77,268 124,513 Other (47,372 ) (67,564 ) (10,649 ) (24,979 ) Total $ 568,407 $ 666,018 $ — $ — Income taxes paid were $6,089,000 , $2,795,000 and $6,936,000 for the years ended December 31, 2017, 2016 and 2015 , respectively. At December 31, 2017 , the TRS had a federal net operating loss carryforward of $106,505,000 available to use on its tax return expiring in the years ending December 31, 2028 through 2037. At December 31, 2017 , the Company had a federal net operating loss carryforward of $76,176,000 available to use on its REIT tax return expiring in the years ending December 31, 2034 through 2036. At December 31, 2017, the TRS had an available alternative minimum tax (“AMT”) credit of $2,500,000 , and the REIT had an available AMT credit of $25,600,000 . On December 22, 2017, President Trump signed the Tax Cuts and Jobs Act. As part of this 2017 tax reform legislation, the corporate AMT tax has been eliminated for years beginning in 2018. However, AMT credits can still be used to offset any regular income tax liability. Fifty percent ( 50% ) of the AMT credits for a tax year in excess of the AMT tax credits allowed to reduce the Company’s regular tax liability for such year are refundable for tax years 2018 through 2020. Any remaining AMT tax credits will be refundable on the Company’s 2021 income tax returns. The Company has recorded a $28,100,000 AMT credit receivable for these credits, and recognized a deferred tax benefit. The Company’s policy is to consider a variety of tax-deferral strategies, including tax deferred exchanges, when evaluating its future tax position. At December 31, 2015, the Company had a full valuation allowance against the deferred tax assets associated with the TRS, with the exception of anticipated 2016 losses on sales of assets owned in the TRS that were offset by the 2016 gains on sales of our interests in entities that develop and manage Military Housing and our equity interests in Barclays Center and the Nets, which were owned by the TRS. The 2015 deferred tax asset was reversed in 2016 when the sales of these assets were completed. The valuation allowance exists because management believes it is more likely than not the Company will not realize these benefits. December 31, 2017 December 31, 2016 (in thousands) Deferred tax liabilities $ 116,829 $ 182,804 Deferred tax assets 286,429 462,979 Less: valuation allowance (169,600 ) (280,175 ) 116,829 182,804 Net deferred tax asset $ — $ — Accounting for Uncertainty in Income Taxes Unrecognized tax benefits represent those tax benefits related to tax positions that have been taken or are expected to be taken in tax returns that are not recognized in the financial statements because management has either concluded it is not more likely than not the tax position will be sustained if audited by the appropriate taxing authority or the amount of the benefit will be less than the amount taken or expected to be taken in its income tax returns. The Company had unrecognized tax benefits of $187,000 at both December 31, 2017 and 2016 . The Company recognizes estimated interest payable on underpayments of income taxes and estimated penalties as components of income tax expense. As of December 31, 2017 and 2016 , the Company had approximately $115,000 and $103,000 , respectively, of accrued interest and penalties related to uncertain income tax positions. The Company recorded income tax expense (benefit) relating to interest and penalties on uncertain tax positions of $12,000 , $(69,000) and $(68,000) for the years ended December 31, 2017, 2016 and 2015 , respectively. The Company’s federal consolidated income tax returns for the year ended December 31, 2014 and subsequent years are subject to examination by the IRS. Certain of the Company’s state returns for the years ended January 31, 2003 through December 31, 2013 and all state returns for the year ended December 31, 2014 and subsequent years are subject to examination by various taxing authorities. A reconciliation of the total amounts of the Company’s unrecognized tax benefits, exclusive of interest and penalties, is summarized in the following table: Unrecognized Tax Benefit December 31, 2017 December 31, 2016 (in thousands) Beginning balance, January 1, $ 187 $ 478 Settlements — — Lapse of statutes of limitation — (291 ) Unrecognized tax benefits balance at December 31, $ 187 $ 187 The total amount of unrecognized tax benefits that would affect the Company’s effective tax rate, if recognized as of December 31, 2017 and 2016 , is $148,000 and $122,000 , respectively. Based upon the Company’s assessment of the outcome of examinations that are in progress, the settlement of liabilities, or as a result of the expiration of the statutes of limitation for certain jurisdictions, it is reasonably possible the related unrecognized tax benefits for tax positions taken regarding previously filed tax returns will change from those recorded at December 31, 2017 . Due to the reasons above, the entire $187,000 of unrecognized benefits could decrease during the next twelve months.

Assets and Liabilities Held for

Assets and Liabilities Held for Sale and Discontinued Operations	12 Months Ended
	Dec. 31, 2017
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Assets and Liabilities Held for Sale and Discontinued Operations The following table summarizes the rental properties included in discontinued operations: Property/Asset Location Period Disposed Years Ended December 31, 2017 2016 2015 Barclays Center Arena and The Nets Brooklyn, New York Q1-2016 — Yes Yes The following table summarizes the operating results related to discontinued operations: Years Ended December 31, 2016 2015 (in thousands) Revenues $ 14,792 $ 138,154 Expenses Operating expenses 12,540 97,021 Depreciation and amortization 23 34,554 12,563 131,575 Interest expense (3,540 ) (40,125 ) Amortization of mortgage procurement costs (61 ) (664 ) Loss before income taxes and loss from unconsolidated entities (1,372 ) (34,210 ) Loss from unconsolidated entities (1,400 ) (40,760 ) Loss before income taxes (2,772 ) (74,970 ) Income tax (benefit) (824 ) (22,498 ) Loss before gain on disposal group (1,948 ) (52,472 ) Gain on disposition of disposal group, net of tax 49,353 — Earnings (loss) from discontinued operations 47,405 (52,472 ) Noncontrolling interests Operating loss from disposal group and rental properties (776 ) (16,962 ) Earnings (loss) from discontinued operations attributable to Forest City Realty Trust, Inc. $ 48,181 $ (35,510 ) The following table summarizes the pre-tax gain (loss) on disposition of the Disposal Group: Years Ended December 31, 2016 2015 (in thousands) The Nets $ 136,247 $ — Barclays Center (56,481 ) — 79,766 — Income tax effect (1) (30,413 ) — $ 49,353 $ — (1) For the year ended December 31, 2016, primarily represents non-cash deferred taxes recognized upon the reversal of the deferred tax asset used to offset the taxable gain on the sales of assets held by the TRS.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The loss from continuing operations attributable to Forest City Realty Trust, Inc. for the year ended December 31, 2016 was allocated solely to holders of common stock as the participating security holders do not share in the losses. The reconciliation of the basic and diluted EPS computations is shown in the following table: Years Ended December 31, 2017 2016 2015 Numerators (in thousands) Earnings (loss) from continuing operations attributable to Forest City Realty Trust, Inc. $ 206,030 $ (206,583 ) $ 531,552 Distributed and undistributed earnings allocated to participating securities (1,677 ) — (10,410 ) Earnings (loss) from continuing operations attributable to common stockholders - Basic $ 204,353 $ (206,583 ) $ 521,142 Undistributed earnings allocated to participating securities 506 — — Preferred distribution on Class A Common Units 709 — — Interest on convertible debt — — 6,606 Earnings (loss) from continuing operations attributable to common stockholders - Diluted $ 205,568 $ (206,583 ) $ 527,748 Net earnings (loss) attributable to Forest City Realty Trust, Inc. $ 206,030 $ (158,402 ) $ 496,042 Distributed and undistributed earnings allocated to participating securities (1,677 ) — (9,715 ) Net earnings (loss) attributable to common stockholders - Basic $ 204,353 $ (158,402 ) $ 486,327 Undistributed earnings allocated to participating securities 506 — — Preferred distribution on Class A Common Units 709 — — Interest on convertible debt — — 6,606 Net earnings (loss) attributable to common stockholders - Diluted $ 205,568 $ (158,402 ) $ 492,933 Denominators Weighted average shares outstanding - Basic 262,510,532 258,509,970 237,559,598 Effect of stock options and performance shares 763,611 — 1,342,524 Effect of convertible Class A Common Units 1,594,238 — — Effect of convertible debt — — 11,946,164 Weighted average shares outstanding - Diluted (1) 264,868,381 258,509,970 250,848,286 Earnings Per Share Earnings (loss) from continuing operations attributable to common stockholders - Basic $ 0.78 $ (0.80 ) $ 2.19 Earnings (loss) from continuing operations attributable to common stockholders - Diluted $ 0.78 $ (0.80 ) $ 2.10 Net earnings (loss) attributable to common stockholders - Basic $ 0.78 $ (0.61 ) $ 2.05 Net earnings (loss) attributable to common stockholders - Diluted $ 0.78 $ (0.61 ) $ 1.97 (1) Incremental shares from restricted stock and convertible securities aggregating 5,923,113 and 9,706,419 for the years ended December 31, 2017 and 2015, respectively, were not included in the computation of diluted EPS because their effect is anti-dilutive. Incremental shares from dilutive options, restricted stock, performance shares and convertible securities aggregating 9,528,889 for the year ended December 31, 2016 were not included in the computation of diluted EPS because their effect is anti-dilutive due to loss from continuing operations. Weighted-average options, restricted stock and performance shares of 1,333,046 , 2,706,145 and 2,392,982 for the years ended December 31, 2017, 2016 and 2015 , respectively, were not included in the computation of diluted EPS because their effect is anti-dilutive under the treasury stock method.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information Real Estate Operations represents the performance of the Company’s core rental real estate portfolio and is comprised of the following reportable operating segments: • Office - owns, acquires and operates office and life science buildings. • Apartments - owns, acquires and operates upscale and middle-market apartments and adaptive re-use developments. • Retail - owns, acquires and operates amenity retail within our mixed-use properties, and remaining regional malls and specialty/urban retail centers. The remaining reportable operating segments consist of the following: • Development develops and constructs office and life science buildings, apartments, condominiums, amenity retail and mixed-use projects. The Development segment includes recently opened operating properties prior to stabilization. and horizontal development and sale of land to residential, commercial and industrial customers primarily at its Stapleton project in Denver, Colorado. • Corporate provides executive oversight and various support services for Operations, Development and Corporate employees. • Other owned and operated non-core investments, including the Barclays Center, a sports and entertainment arena located in Brooklyn, New York (“Arena”) (sold in January 2016), the Company’s equity method investment in the Brooklyn Nets (the “Nets”) (sold in January 2016), and military housing operations (sold in February 2016). Segment Transfers The Development segment includes projects in development, projects under construction along with recently opened operating properties prior to stabilization. Projects will be reported in their applicable operating segment (Office, Apartments or Retail) beginning on January 1 of the year following stabilization. The Company generally defines stabilized properties as achieving 92% or greater occupancy or having been open and operating for one or two years, depending on the size of the project. The following tables summarize financial data for the Company’s reportable operating segments. All amounts are presented in thousands. December 31, 2017 December 31, 2016 Identifiable Assets Office $ 3,025,810 $ 3,192,840 Apartments 2,246,479 2,406,768 Retail 368,353 521,015 Total Operations 5,640,642 6,120,623 Development 2,020,273 1,799,138 Corporate 402,372 308,836 $ 8,063,287 $ 8,228,597 Years Ended December 31, Years Ended December 31, 2017 2016 2015 2017 2016 2015 Revenues Operating Expenses Office $ 449,636 $ 463,855 $ 425,052 $ 169,792 $ 185,983 $ 182,677 Apartments 286,358 291,615 267,633 126,317 137,313 142,926 Retail 53,335 79,660 138,955 37,710 52,127 90,489 Total Operations 789,329 835,130 831,640 333,819 375,423 416,092 Development 122,597 90,835 114,722 91,929 81,032 101,031 Corporate — — — 96,544 94,391 100,099 Other — 3,518 31,869 — 2,730 8,130 $ 911,926 $ 929,483 $ 978,231 $ 522,292 $ 553,576 $ 625,352 Depreciation and Amortization Capital Expenditures Office $ 125,825 $ 134,323 $ 109,176 $ 58,235 $ 40,066 $ 56,354 Apartments 77,956 77,556 78,593 29,569 19,383 27,722 Retail 9,343 20,662 51,326 4,608 9,885 9,999 Total Operations 213,124 232,541 239,095 92,412 69,334 94,075 Development 32,603 16,902 10,481 333,211 507,123 442,289 Corporate 2,626 1,279 2,582 10,218 99 205 Other — 126 767 — — — $ 248,353 $ 250,848 $ 252,925 $ 435,841 $ 576,556 $ 536,569 The Company uses Adjusted Earnings Before Interest, Taxes, Depreciation and Amortization ("EBITDA") to manage its business and report its operating results by segment. Adjusted EBITDA, a non-GAAP measure, is defined as net earnings excluding the following items at the Company's ownership: i) non-cash charges for depreciation and amortization; ii) interest expense; iii) amortization of mortgage procurement costs; iv) income taxes; v) impairment of real estate; vi) gains or losses from extinguishment of debt; vii) gain (loss) on full or partial disposition of rental properties, development projects and other investments; viii) gains or losses on change in control of interests; ix) other transactional items, including organizational transformation and termination benefits; and x) the Nets pre-tax EBITDA. The Company believes that Adjusted EBITDA is an appropriate measure to assess operating performance by segment as it represents ongoing key operating components of each segment without regard to how the business is financed. The Company’s Chief Executive Officer, the chief operating decision maker, uses Adjusted EBITDA, as presented, to assess performance of the Company’s real estate assets by operating segment because it provides information on the financial performance of the core real estate portfolio operations, development, corporate general and administrative expenses and interest and other income derived from the Company's investments. Adjusted EBITDA measures the profitability of each real estate segment in operations based on the process of collecting rent and paying operating expenses and represents the equivalent of Net Operating Income (“NOI”), as all property level interest expense is reported in the Corporate segment. NOI by operating segment is discussed in the Net Operating Income section of Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations (“MD&A”) of this Form 10-K. For the development segment, adjusted EBITDA measures the profitability of our land development sales activity and any recently opened unstabilized properties, offset by development expenses that do not qualify for capitalization. Interest expense is monitored and evaluated by the chief operating decision maker on an overall company-wide basis and is not a factor in evaluating individual segment performance. The reconciliations of net earnings (loss) to Adjusted EBITDA by segment are shown in the following tables. All amounts are presented in thousands. Year Ended December 31, 2017 Office Apartments Retail Total Operations Development Corporate Other Total Net earnings (loss) attributable to Forest City Realty Trust, Inc. $ 165,040 $ 179,036 $ 152,698 $ 496,774 $ (59,398 ) $ (231,346 ) $ — $ 206,030 Depreciation and amortization 129,202 89,885 65,052 284,139 26,620 2,626 — 313,385 Interest expense — — — — — 198,777 — 198,777 Amortization of mortgage procurement costs — — — — — 7,469 — 7,469 Income tax benefit — — — — — (21,422 ) — (21,422 ) Impairment of consolidated real estate — — — — 44,288 — — 44,288 Impairment of unconsolidated real estate — — 10,600 10,600 — — — 10,600 Loss on extinguishment of debt — — — — — 4,514 — 4,514 Net (gain) loss on disposition of full or partial interests in rental properties (2,589 ) (6,065 ) (37,467 ) (46,121 ) — — (46,121 ) Gain on disposition of unconsolidated entities (1,437 ) (71,037 ) (36,363 ) (108,837 ) — — — (108,837 ) Organizational transformation and termination benefits — — — — — 34,395 — 34,395 Adjusted EBITDA Attributable to Forest City Realty Trust, Inc. $ 290,216 $ 191,819 $ 154,520 $ 636,555 $ 11,510 $ (4,987 ) $ — $ 643,078 Year Ended December 31, 2016 Office Apartments Retail Total Operations Development Corporate Other Total Net earnings (loss) attributable to Forest City Realty Trust, Inc. $ 138,282 $ 102,249 $ (15,813 ) $ 224,718 $ (182,716 ) $ (422,592 ) $ 222,188 $ (158,402 ) Depreciation and Amortization 134,511 94,622 78,818 307,951 12,182 1,279 302 321,714 Interest Expense — — — — — 221,812 — 221,812 Amortization of mortgage procurement costs — — — — — 8,680 — 8,680 Income tax expense — — — — — 85,105 — 85,105 Interest rate swap breakage fee — — — — — 24,635 — 24,635 Impairment of consolidated real estate 19,700 2,100 133,795 155,595 1,230 — — 156,825 Impairment of unconsolidated real estate — — — — 306,400 — — 306,400 Loss on extinguishment of debt — — — — — 33,863 — 33,863 Net (gain) loss on disposition of full or partial interests in development project — — — — (136,687 ) — — (136,687 ) Net (gain) loss on disposition of full or partial interests in rental properties (13,782 ) (2,333 ) (15,216 ) (31,331 ) 324 — (141,675 ) (172,682 ) Gain on disposition of unconsolidated entities — — (12,613 ) (12,613 ) (553 ) — — (13,166 ) Organizational transformation and termination benefits — — — — — 31,708 — 31,708 Discontinued operations: Depreciation and Amortization - Real Estate — — — — — — 35 35 Loss on disposition of rental properties — — — — — — 56,481 56,481 Net gain on disposition of partial interest in other investment - Nets — — — — — — (136,247 ) (136,247 ) Nets pre-tax EBITDA — — — — — — 1,400 1,400 Adjusted EBITDA Attributable to Forest City Realty Trust, Inc. $ 278,711 $ 196,638 $ 168,971 $ 644,320 $ 180 $ (15,510 ) $ 2,484 $ 631,474 Year Ended December 31, 2015 Office Apartments Retail Total Operations Development Corporate Other Total Net earnings (loss) attributable to Forest City Realty Trust, Inc. $ 576,328 $ 82,944 $ (321,052 ) $ 338,220 $ (26,107 ) $ 198,327 $ (14,398 ) 496,042 Depreciation and Amortization 112,825 91,378 99,886 304,089 12,733 2,582 2,797 322,201 Interest Expense — — — — — 264,299 — 264,299 Amortization of mortgage procurement costs — — — — — 10,600 — 10,600 Income tax benefit — — — — — (603,597 ) — (603,597 ) Impairment of consolidated real estate 28,146 8,423 398,558 435,127 16,307 — — 451,434 Impairment of unconsolidated real estate — 12,460 — 12,460 1,384 — — 13,844 Loss on extinguishment of debt — — — — — 65,103 — 65,103 Net (gain) loss on disposition of full or partial interests in rental properties (1,746 ) — — (1,746 ) — — — (1,746 ) Gain on disposition of unconsolidated entities (1,009 ) (19,284 ) — (20,293 ) — — — (20,293 ) (Gain) loss on change in control of interests (463,643 ) (24,041 ) — (487,684 ) 1,405 — — (486,279 ) Organizational transformation and termination benefits — — — — — 48,125 — 48,125 Discontinued operations: Depreciation and Amortization — — — — — — 20,104 20,104 Nets pre-tax EBITDA — — — — — — 40,760 40,760 Adjusted EBITDA Attributable to Forest City Realty Trust, Inc. $ 250,901 $ 151,880 $ 177,392 $ 580,173 $ 5,722 $ (14,561 ) $ 49,263 $ 620,597

Subsequent Event Subsequent Eve

Subsequent Event Subsequent Event	12 Months Ended
	Dec. 31, 2017
Subsequent Event [Abstract]
Subsequent Events [Text Block]	Subsequent Event On January 31, 2018, our 50% noncontrolling partner at Bayside Village , an apartment community in San Francisco, CA, closed on a transaction where they sold the majority of their 50% ownership interest to an unrelated third party. Prior to this transaction, the Company fully consolidated the property, as the outside partner, in accordance with the partnership agreement, lacked any substantive participating rights. Simultaneously with the sale, the Company amended the partnership agreement to grant substantive participating rights to the new outside partner and received a cash payment of $24,000,000 in connection with such amendment. Based on the substantive participating rights held by the new outside partner, a reconsideration event as defined in the consolidation standards has occurred and will be evaluated in the first quarter of 2018.

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2017
Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS Description Balance at Beginning of Period Additions Charged to Costs and Expenses Deductions Balance at End of Period (in thousands) Allowance for doubtful accounts receivable December 31, 2017 $ 5,324 $ 343 $ 2,270 $ 3,397 December 31, 2016 $ 9,025 $ 1,628 $ 5,329 $ 5,324 December 31, 2015 $ 10,771 $ 2,744 $ 4,490 $ 9,025 Valuation reserve on other investments December 31, 2017 $ 5,355 $ 10 $ 25 $ 5,340 December 31, 2016 $ 5,336 $ 19 $ — $ 5,355 December 31, 2015 $ 5,320 $ 16 $ — $ 5,336 Valuation allowances for deferred tax assets (1) December 31, 2017 $ 280,175 $ 13,466 $ 124,041 $ 169,600 December 31, 2016 $ 152,449 $ 163,330 $ 35,604 $ 280,175 December 31, 2015 $ 53,735 $ 145,351 $ 46,637 $ 152,449 (1) See Note V – Income Taxes in the Notes to Consolidated Financial Statements in Item 8 of this Form 10-K for additional information.

Real Estate and Accumulated Dep

Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2017
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Real Estate and Accumulated Depreciation	(c) Financial Statements Schedules (continued) SCHEDULE III – REAL ESTATE AND ACCUMULATED DEPRECIATION Forest City Realty Trust, Inc. and Subsidiaries Initial Cost to Company Cost Capitalized Subsequent to Acquisition Gross Amount at Which Carried at Close of December 31, 2017 Accumulated Depreciation at December 31, 2017 (C) Date of Construction/ Acquisition Range of Lives on Which Depreciation in Latest Income Statement is Computed Name Location Amount of Encumbrance at December 31, 2017 Land and Improvements Buildings and Improvements Improvements and Carrying Costs Land and Improvements Buildings and Improvements Total (A)(B) Office (in thousands) Atlantic Terminal Office Brooklyn, NY $ 102,542 $ — $ 108,940 $ 6,131 $ — $ 115,071 $ 115,071 $ 30,743 2004 (1) Ballston Common Office Center Arlington, VA — 7,301 45,964 7,395 7,301 53,359 60,660 11,957 2005 (1) Edgeworth Building Richmond, VA 19,597 942 29,353 4,002 951 33,346 34,297 7,222 2006 (1) Glen Forest Office Park Richmond, VA 59,131 11,766 88,632 15,515 11,841 104,072 115,913 29,678 2007 (1) Harlem Office Manhattan, NY — — 31,672 8,422 — 40,094 40,094 10,745 2003 (1) Johns Hopkins - 855 North Wolfe Street Baltimore, MD 64,085 7,314 76,318 23,413 7,314 99,731 107,045 20,032 2008 (1) Johns Hopkins Parking Garage Baltimore, MD — 835 13,674 1,503 835 15,177 16,012 1,531 2012 (1) Fidelity Investments Albuquerque, NM 12,230 5,003 29,872 293 5,003 30,165 35,168 5,603 2008 (1) MetroTech Campus One MetroTech Center Brooklyn, NY — — 212,153 72,803 23,543 261,413 284,956 134,904 1991 (1) Two MetroTech Center Brooklyn, NY 68,941 — 155,280 34,932 7,137 183,075 190,212 92,843 1990 (1) Nine MetroTech Center Brooklyn, NY 55,196 — 64,303 13,510 380 77,433 77,813 29,796 1997 (1) Eleven MetroTech Center Brooklyn, NY — — 41,290 25,554 6,270 60,574 66,844 30,510 1995 (1) Twelve MetroTech Center Brooklyn, NY — — 42,344 16,092 1,847 56,589 58,436 15,279 2004 (1) Fifteen MetroTech Center Brooklyn, NY 154,848 3,762 163,414 8,482 — 175,658 175,658 49,455 2003 (1) New York Times Manhattan, NY — 91,737 375,931 138,494 141,479 464,683 606,162 95,791 2007 (1) One Pierrepont Plaza Brooklyn, NY — — 86,863 108,715 558 195,020 195,578 120,714 1988 (1) Station Square Commerce Court Pittsburgh, PA 22,710 3,432 20,873 9,243 3,441 30,107 33,548 10,861 2007 (1) Landmark Building Pittsburgh, PA 25,140 5,989 27,519 13,643 15,919 31,232 47,151 15,262 1994 (1) University of Pennsylvania Philadelphia, PA 35,788 — 41,146 10,707 — 51,853 51,853 13,506 2004 (1) University Park at MIT 26 Landsdowne Street Cambridge, MA 27,208 90 79,470 1,866 135 81,291 81,426 5,397 1987 (1) 35 Landsdowne Street Cambridge, MA 62,676 196 181,779 770 258 182,487 182,745 13,313 2002 (1) 40 Landsdowne Street Cambridge, MA 63,581 236 192,897 1,787 301 194,619 194,920 14,273 2003 (1) 45/75 Sidney Street Cambridge, MA 85,891 793 289,942 22,656 877 312,514 313,391 22,302 1999 (1) 64 Sidney Street Cambridge, MA 50,624 50 110,850 4,744 89 115,555 115,644 11,084 1990 (1) 65 Landsdowne Street Cambridge, MA 63,919 198 125,278 99 236 125,339 125,575 8,545 2001 (1) 88 Sidney Street Cambridge, MA 35,798 274 145,426 490 318 145,872 146,190 13,028 2002 (1) Miscellaneous Investments Various — — 1,698 11,820 — 13,518 13,518 9,533 Various (1) Office Subtotal $ 1,009,905 $ 139,918 $ 2,782,881 $ 563,081 $ 236,033 $ 3,249,847 $ 3,485,880 $ 823,907 (c) Financial Statements Schedules (continued) SCHEDULE III – REAL ESTATE AND ACCUMULATED DEPRECIATION Forest City Realty Trust, Inc. and Subsidiaries Initial Cost to Company Cost Capitalized Subsequent to Acquisition Gross Amount at Which Carried at Close of December 31, 2017 Accumulated Depreciation at December 31, 2017 (C) Date of Construction/ Acquisition Range of Lives on Which Depreciation in Latest Income Statement is Computed Name Location Amount of Encumbrance at December 31, 2017 Land and Improvements Buildings and Improvements Improvements and Carrying Costs Land and Improvements Buildings and Improvements Total (A)(B) Retail Brooklyn Commons Brooklyn, NY 17,143 — 23,794 1,289 19,618 5,465 25,083 2,226 2004 (1) Shops at Atlantic Center Site V Brooklyn, NY — — 3,238 1,485 1,047 3,676 4,723 1,603 1998 (1) Station Square Pittsburgh, PA 7,540 2,622 9,965 25,710 6,913 31,384 38,297 17,020 1994 (1) The Yards Boilermaker Shops Washington, D.C. 11,135 529 12,468 6,446 527 18,916 19,443 1,895 2012 (1) Lumber Shed Washington, D.C. 9,745 306 12,820 1,500 306 14,320 14,626 1,465 2013 (1) Miscellaneous Investments Various 1,646 — 1,818 — — 1,818 1,818 1,783 Various (1) Retail Subtotal $ 47,209 $ 3,457 $ 64,103 $ 36,430 $ 28,411 $ 75,579 $ 103,990 $ 25,992 Apartments 100 (100 Landsdowne) Cambridge, MA $ 44,117 $ 728 $ 60,020 $ 951 $ 892 $ 60,807 $ 61,699 $ 18,119 2005 (1) 1111 Stratford Stratford, CT — 2,414 15,798 5,553 2,518 21,247 23,765 3,764 2013 (1) 1251 S. Michigan Chicago, IL 9,498 97 13,978 1,091 106 15,060 15,166 4,129 2006 (1) 2175 Market Street San Fransisco, CA 29,803 3,793 34,508 921 3,855 35,367 39,222 4,691 2014 (1) 91 Sidney Cambridge, MA 28,921 213 42,276 1,362 269 43,582 43,851 5,114 2002 (1) American Cigar Lofts Richmond, VA 11,259 1,395 23,533 1,870 855 25,943 26,798 6,362 2000 (1) Aster Conservatory Green Denver, CO 35,806 1,325 13,125 33,301 1,599 46,152 47,751 7,774 2013 (1) Aster Town Center North Denver, CO 17,629 611 20,705 — 611 20,705 21,316 1,970 2015 (1) Bayside Village San Francisco, CA 126,896 153,894 282,807 3,333 153,576 286,458 440,034 24,961 1988 (1) Botanica Eastbridge Denver, CO 12,610 765 13,698 542 772 14,233 15,005 2,837 2012 (1) Cameron Kinney Lofts Richmond, VA — 2,340 23,206 4,126 2,502 27,170 29,672 7,123 2007 (1) Cedar Place Lansing, MI 3,585 399 7,000 558 399 7,558 7,957 4,569 1974 (1) Cherry Tree Strongsville, OH 16,231 4,838 22,028 979 4,839 23,006 27,845 2,952 1996 (1) Chestnut Lake Strongsville, OH 21,950 5,494 16,466 10,882 5,684 27,158 32,842 3,060 1969 (1) Consolidated-Carolina Lofts Richmond, VA 20,623 1,028 30,425 2,145 1,046 32,552 33,598 10,016 2003 (1) Cutter’s Ridge Richmond, VA — 389 4,356 (93 ) 400 4,252 4,652 1,492 2006 (1) Drake Tower Philadelphia, PA 24,897 1,353 38,104 9,436 1,353 47,540 48,893 16,287 1998 (1) Easthaven at the Village Beachwood, OH 23,775 7,919 39,768 8,331 8,113 47,905 56,018 24,034 1994 (1) Hamel Mill Lofts Haverhill, MA 47,859 3,974 72,902 3,685 3,416 77,145 80,561 15,898 2008 (1) Heritage San Diego, CA — 7,433 42,202 10,106 7,505 52,236 59,741 20,226 2002 (1) Hummingbird Pointe Apartments Parma, OH — 330 5,059 18,434 1,355 22,468 23,823 12,012 1972 (1) Independence Place I Parma Heights, OH 3,852 210 6,671 1,609 240 8,250 8,490 4,867 1973 (1) Independence Place II Parma Heights, OH 3,334 498 3,931 5,446 774 9,101 9,875 3,239 2003 (1) KBL Cambridge, MA 15,604 716 23,645 5,349 719 28,991 29,710 18,939 1990 (1) Knolls Orange, CA 31,187 53 23,759 826 54 24,584 24,638 13,429 1995 (1) Lofts 23 Cambridge, MA 5,636 221 17,026 372 330 17,289 17,619 5,843 2005 (1) Lofts at 1835 Arch Philadelphia, PA 36,751 2,076 27,430 13,236 2,082 40,660 42,742 13,786 2001 (1) Lucky Strike Lofts Richmond, VA 16,759 1,105 34,095 1,244 1,107 35,337 36,444 8,520 2008 (1) (c) Financial Statements Schedules (continued) SCHEDULE III – REAL ESTATE AND ACCUMULATED DEPRECIATION Forest City Realty Trust, Inc. and Subsidiaries Initial Cost to Company Cost Capitalized Subsequent to Acquisition Gross Amount at Which Carried at Close of December 31, 2017 Accumulated Depreciation at December 31, 2017 (C) Date of Construction/ Acquisition Range of Lives on Which Depreciation in Latest Income Statement is Computed Name Location Amount of Encumbrance at December 31, 2017 Land and Improvements Buildings and Improvements Improvements and Carrying Costs Land and Improvements Buildings and Improvements Total (A)(B) Mercantile Place on Main Dallas, TX 33,977 8,876 75,478 9,037 8,805 84,586 93,391 21,163 2008 (1) Metro 417 Los Angeles, CA 44,699 8,545 67,326 5,873 8,551 73,193 81,744 19,893 2005 (1) Midtown Towers Parma, OH 11,699 1,215 11,091 14,934 1,316 25,924 27,240 12,769 1969 (1) Museum Towers Philadelphia, PA 28,728 3,474 18,158 5,239 1,331 25,540 26,871 10,630 1997 (1) North Church Towers and Gardens Parma Heights, OH — 789 4,037 3,917 887 7,856 8,743 2,783 2009 (1) One Franklin Town Philadelphia, PA 54,839 1,658 31,489 11,471 1,854 42,764 44,618 23,070 1988 (1) Pavilion Chicago, IL 47,361 5,250 29,505 18,713 5,251 48,217 53,468 16,981 1992 (1) Presidio Landmark San Francisco, CA 41,950 2,060 92,687 5,272 2,068 97,951 100,019 20,393 2010 (1) Queenswood Corona, NY 27,924 321 39,243 1,666 327 40,903 41,230 20,600 1990 (1) River Lofts at Ashton Mill Cumberland, RI — 2,885 33,844 12,811 3,250 46,290 49,540 13,752 2005 (1) Sky55 Chicago, IL 68,031 3,965 80,930 4,469 4,016 85,348 89,364 26,162 2006 (1) Stratford Crossings Wadsworth, OH — 2,813 27,357 585 2,826 27,929 30,755 3,288 2007 (1) The Aster Town Center Denver, CO 8,284 487 9,901 367 494 10,261 10,755 2,100 2012 (1) The Continental Dallas, TX 35,271 1,586 48,455 (1,526 ) 1,586 46,929 48,515 8,543 2013 (1) The Met Los Angeles, CA 38,639 4,420 36,557 11,042 4,501 47,518 52,019 26,460 1989 (1) The Uptown Oakland, CA 163,851 — 138,710 2,249 963 139,996 140,959 18,052 2013 (1) The Wilson Dallas, TX — 2,217 16,565 4,455 1,937 21,300 23,237 5,662 2007 (1) The Yards Foundry Lofts Washington, D.C. 46,627 2,086 52,806 7,847 2,096 60,643 62,739 9,469 2011 (1) Twelve12 Washington, D.C. 64,768 5,444 106,509 3,489 5,479 109,963 115,442 11,570 2014 (1) Town Center Denver, CO 35,183 3,436 63,073 5,517 3,356 68,670 72,026 23,636 2004 (1) Winchester Lofts New Haven, CT 21,776 — 45,650 387 4 46,033 46,037 5,574 2014 (1) Miscellaneous Investments Various 1,595 — 2,995 18,638 — 21,633 21,633 13,922 Various (1) Apartments Subtotal $ 1,363,784 $ 267,138 $ 1,990,887 $ 292,047 $ 267,869 $ 2,282,203 $ 2,550,072 $ 582,485 Land Inventory Stapleton Denver, CO $ — $ 55,501 $ — $ — $ 55,501 $ — $ 55,501 $ — Various N/A Commercial Outlots Various — 1,795 — — 1,795 — 1,795 — Various N/A Land Inventory Subtotal $ — $ 57,296 $ — $ — $ 57,296 $ — $ 57,296 $ — Corporate and Other Equipment Corporate Office Various $ — $ — $ 10,626 $ 13,188 $ — $ 23,814 $ 23,814 $ 10,503 Various (1) (c) Financial Statements Schedules (continued) SCHEDULE III – REAL ESTATE AND ACCUMULATED DEPRECIATION Forest City Realty Trust, Inc. and Subsidiaries Initial Cost to Company Cost Capitalized Subsequent to Acquisition Gross Amount at Which Carried at Close of December 31, 2017 Accumulated Depreciation at December 31, 2017 (C) Date of Construction/ Acquisition Range of Lives on Which Depreciation in Latest Income Statement is Computed Name Location Amount of Encumbrance at December 31, 2017 Land and Improvements Buildings and Improvements Improvements and Carrying Costs Land and Improvements Buildings and Improvements Total (A)(B) Recently-Opened Properties/Redevelopment Office 1812 Ashland Ave Baltimore, MD $ 33,342 $ 7,628 $ 42,574 $ 1,585 $ 7,628 $ 44,159 $ 51,787 $ 2,383 2016 (1) The Bridge at Cornell Tech Roosevelt Island, NY 79,659 — 69,481 — — 69,481 69,481 780 2017 (1) Apartments 461 Dean Street Brooklyn, NY — 19,307 109,208 31,969 22,584 137,900 160,484 6,988 2016 (1) Axis Los Angeles, CA 63,956 14,848 62,018 — 14,848 62,018 76,866 781 2017 (1) Blossom Plaza Los Angeles, CA 4,790 3,237 81,432 146 3,261 81,554 84,815 4,648 2016 (1) Eliot on 4th Washington, D.C. 62,449 8,439 110,347 — 8,954 109,832 118,786 2,779 2017 (1) Kapolei Lofts Kapolei, HI 91,470 34,051 110,288 1,018 34,060 111,297 145,357 10,554 2015 (1) Mint Town Center Denver, CO 48,066 — 30,709 — — 30,709 30,709 282 2017 (1) NorthxNorthwest Philadelphia, PA 64,317 2,722 65,977 45,970 2,952 111,717 114,669 3,685 2016 (1) The Yards - Arris Washington, D.C. 76,361 9,191 111,825 3,856 9,191 115,681 124,872 7,751 2016 (1) The Yards - Marina Washington, D.C. — — 3,044 — — 3,044 3,044 544 2016 (1) Retail The Yards - District Winery Washington, D.C. — 326 9,655 — 326 9,655 9,981 101 2017 (1) Recently-Opened Properties/Redevelopment Subtotal $ 524,410 $ 99,749 $ 806,558 $ 84,544 $ 103,804 $ 887,047 $ 990,851 $ 41,276 Construction Projects Office The Bridge at Cornell Tech Roosevelt Island, NY — — 79,976 — — 79,976 79,976 — Ongoing N/A Apartments Ardan Dallas, TX 30,808 10,877 82,141 — 10,877 82,141 93,018 — Ongoing N/A Aster Conservatory Green North Denver, CO — 4,298 1,413 — 4,298 1,413 5,711 — Ongoing N/A Axis Los Angeles, CA — 12,281 51,425 — 12,281 51,425 63,706 — Ongoing N/A Mint Town Center Denver, CO — 619 51,674 — 619 51,674 52,293 — Ongoing N/A The Yards - The Guild Washington, D.C. 13,315 11,377 31,483 — 11,377 31,483 42,860 — Ongoing N/A Development Projects Office The Science + Technology Park at Johns Hopkins Baltimore, MD — 5,386 16,483 — 5,386 16,483 21,869 — Ongoing N/A Mixed-use 5M San Francisco, CA — 20,840 32,802 — 20,840 32,802 53,642 — Ongoing N/A Pier 70 San Francisco, CA — — 44,198 — — 44,198 44,198 — Ongoing N/A The Yards Washington, D.C. 3,865 3,780 77,714 — 3,780 77,714 81,494 — Ongoing N/A Waterfront Station Washington, D.C. — 7,431 13,226 — 7,431 13,226 20,657 — Ongoing N/A Miscellaneous Investments Various 5,065 881 8,247 — 881 8,247 9,128 — Various N/A Construction and Development Subtotal $ 53,053 $ 77,770 $ 490,782 $ — $ 77,770 $ 490,782 $ 568,552 $ — Total Real Estate $ 2,998,361 $ 645,328 $ 6,145,837 $ 989,290 $ 771,183 $ 7,009,272 $ 7,780,455 $ 1,484,163 (A) The aggregate cost at December 31, 2017 for federal income tax purposes was $5,381,339 . For (B) and (C) refer to the following page. (1) Depreciation is computed based upon the following estimated useful lives: Years Building and improvements\ 30 – 50 Equipment and fixtures 5 – 15 Tenant improvements Shorter of useful life or applicable lease term Years Ended December 31, 2017 2016 2015 (in thousands) (B) Reconciliations of total real estate carrying value are as follows: Balance at beginning of period $ 7,915,565 $ 9,613,342 $ 8,328,987 Additions during period - Improvements 347,363 574,816 621,127 Acquisitions — — 1,254,270 347,363 574,816 1,875,397 Deductions during period - Cost of real estate sold or retired (436,589 ) (1,256,873 ) (105,927 ) Cost of real estate in connection with disposal of partial interests — (824,165 ) — Other deductions, primarily due to impairments (45,884 ) (191,555 ) (485,115 ) (482,473 ) (2,272,593 ) (591,042 ) Balance at end of period $ 7,780,455 $ 7,915,565 $ 9,613,342 (C) Reconciliations of accumulated depreciation are as follows: Balance at beginning of period $ 1,442,006 $ 1,734,382 $ 1,555,965 Additions during period - Charged to profit or loss 215,391 207,297 241,654 Net other additions (deductions) during period - Acquisitions, retirements, sales or disposals (173,234 ) (499,673 ) (63,237 ) Balance at end of period $ 1,484,163 $ 1,442,006 $ 1,734,382

Mortgage Loan on Real Estate

Mortgage Loan on Real Estate	12 Months Ended
	Dec. 31, 2017
Mortgage Loan on Real Estate [Abstract]
Mortgage Loans on Real Estate, by Loan Disclosure [Text Block]	SCHEDULE IV – MORTGAGE LOAN ON REAL ESTATE (in thousands) Description Interest Rate Final Maturity Date Periodic Payment Terms Prior Lien Face Amount of Mortgage Carrying Amount of Mortgage (3) Principal Amount of Loan Subject to Delinquent Principal or Interest First mortgage Shops at Northfield at Stapleton Denver, Colorado (1) 4.25% April 2019 Interest only $ — $ 36,935 $ 36,935 $ — Second mortgage Barclays Center Arena Brooklyn, New York (2) 4.50% January 2019 Interest only 482,000 92,600 92,600 — Total $ 482,000 $ 129,535 $ 129,535 $ — (1) There is no prior lien at December 31, 2017 . (2) The first mortgage loan is not held by the Company. Accordingly, the prior lien amount is estimated at December 31, 2017 . (3) For Federal income tax purposes, the aggregate cost of the investment in mortgage loans on real estate is the carrying amount, as disclosed in the schedule. Changes in mortgage loans are summarized below Years Ended December 31, 2017 2016 2015 (in thousands) Balance at beginning of period $ 92,600 $ — $ — Addition during period: New mortgage loan 36,935 92,600 — Deduction during period — — — Balance at end of period $ 129,535 $ 92,600 $ —

Summary of Significant Accoun42

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of Forest City Realty Trust, Inc., its wholly-owned subsidiaries and entities in which it has a controlling interest in accordance with accounting principles generally accepted in the United States of America (“GAAP”). All intercompany balances and transactions have been eliminated in consolidation. The accounting guidance for consolidation of variable interest entities (“VIEs”) requires an ongoing reassessment of determining whether a variable interest gives a company a controlling financial interest in a VIE. VIEs are entities in which the equity investors do not have sufficient equity at risk to finance their endeavors without additional financial support or the holders of the equity investment at risk do not have a controlling financial interest. The Company continuously reassesses whether or not it has the (a) power to direct the activities of the VIE that most significantly affect its economic performance and (b) the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions in certain circumstances that affect amounts reported in the accompanying consolidated financial statements and related notes. Some of the critical estimates made by the Company include, but are not limited to, determination of the primary beneficiary of VIEs, estimates of useful lives for long-lived assets, reserves for collection on accounts and notes receivable and other investments, gain on change in control of interests, impairment of real estate and other-than-temporary impairments on equity method investments. Actual results could differ from those estimates.
Reclassifications	Reclassifications Certain prior period amounts in the accompanying consolidated financial statements have been reclassified to conform to the current year’s presentation.
New Accounting Guidance	New Accounting Guidance In March 2016, the Financial Accounting Standards Board (“FASB”) issued an amendment to the accounting guidance to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification awards as either equity or liabilities, and classification on the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. The adoption of this guidance effective January 1, 2017 did not have a material impact on the Company’s consolidated financial statements. In August 2016, the FASB issued an amendment to the accounting guidance on the classification of certain transactions on the statement of cash flows where diversity in practice previously existed. The guidance addresses certain specific cash flow issues, including, but not limited to, debt prepayment or debt extinguishment costs and distributions received from equity method investments. This guidance is effective for fiscal years, and for interim reporting periods within those fiscal years, beginning after December 15, 2017. Early adoption was permitted, and the Company elected to adopt this guidance using the retrospective transition method effective January 1, 2017. The adoption of this guidance did not have a material impact the Company’s Consolidated Statements of Cash Flows. In January 2017, the FASB issued an amendment to the accounting guidance for business combinations to clarify the definition of a business. The objective of this guidance is to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. This guidance is effective for annual periods beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted, and the Company has elected to adopt this guidance effective January 1, 2017 on a prospective basis. The impact on the Company’s consolidated financial statements resulting from the adoption of this guidance will depend on the Company’s level of acquisitions, but will most likely increase the number of acquisitions accounted for as asset acquisitions rather than business combinations. The following new accounting pronouncements will be adopted on January 1, 2018: In May 2014, the FASB issued an amendment to the accounting guidance for revenue from contracts with customers. The core principle of this guidance is an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance defines steps an entity should apply to achieve the core principle. This guidance is effective for annual reporting periods beginning after December 15, 2017 and interim reporting periods within that annual period and allows for both retrospective and modified retrospective methods of adoption. The Company will adopt this guidance as of January 1, 2018 using the modified retrospective method. Rental revenue from lease contracts represents a significant portion of the Company’s total revenues and is a specific scope exception provided by this guidance. However, common area maintenance and other tenant reimbursable expenses provided to the lessee are considered a non-lease component and will be required to be separated from rental revenue and recorded on a separate financial statement line item upon adoption of the new accounting guidance on leases discussed below. The Company has completed its analysis and has concluded the adoption of this guidance will not result in a material impact on the Company’s consolidated financial statements or disclosures. In November 2016, the FASB issued an amendment to the accounting guidance on the classification and presentation of changes in restricted cash on the statement of cash flows. The guidance requires restricted cash to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown in the statement of cash flows. This guidance is effective for fiscal years, and for interim reporting periods within those fiscal years, beginning after December 15, 2017. The Company will adopt this guidance as of January 1, 2018 using the retrospective transition method. The adoption of this guidance will significantly increase the combined beginning and ending period cash and restricted cash balances as presented and will remove the effects of the change in restricted cash as previously presented in Company’s Consolidated Statements of Cash Flows. In February 2017, the FASB issued an amendment to the accounting guidance on the derecognition of nonfinancial assets. The guidance clarifies the definition of an in substance nonfinancial asset and the recognition of gains and losses from the transfer of nonfinancial assets and for partial sales of nonfinancial assets, which would include real estate. This guidance is effective for fiscal years, and for interim reporting periods within those fiscal years, beginning after December 15, 2017. The Company will adopt this guidance using the modified retrospective method on January 1, 2018. The impact on the Company’s consolidated financial statements resulting from the adoption of this guidance will depend on the level of real estate sales. In August 2017, the FASB issued an amendment to the accounting guidance on derivatives and hedging activities. The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. The transition method is a modified retrospective approach that will require the Company to recognize the cumulative effect of initially applying the guidance as an adjustment to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings as of the beginning of the fiscal year that an entity adopts the update. The Company has elected to early adopt the guidance on January 1, 2018. The adoption of this guidance will not have a material impact on the Company’s consolidated financial statements. The following new accounting pronouncement will be adopted on its respective effective date: In February 2016, the FASB issued an amendment to the accounting guidance on leases. This guidance sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new guidance requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to the current guidance for operating leases. The new guidance requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. The guidance is expected to impact the Company’s consolidated financial statements as the Company has certain operating and land lease arrangements for which it is the lessee. The new guidance supersedes the previous leases accounting standard. The guidance is effective on January 1, 2019. The adoption of the new guidance is expected to have an impact on the consolidated financial statements as the Company has material ground lease arrangements, as well as other lease agreements. In addition, the Company believes it will be precluded from capitalizing its internal leasing costs, as the costs are not expected to be directly incremental to the successful execution of a lease, as required by the new guidance. The Company is in the process of evaluating the impact of this guidance. In January 2018, the FASB issued a proposal for comment that would make targeted improvements to the new accounting guidance on leases providing lessors with a practical expedient by class of underlying assets to not separate non-lease components from the lease component. Such practical expedient would be limited to circumstances in which (i) the timing and pattern of revenue recognition are the same for the non-lease component and the related lease component and (ii) the combined single lease component would be classified as an operating lease. If the exposed practical expedient is issued in its existing form, the Company expects to elect the practical expedient which would allow the Company the ability to combine the lease and non-lease components if the underlying asset meets the two criteria above.
Acquisition of Rental Properties	Acquisition of Rental Properties Upon acquisition of a rental property, the purchase price is allocated to net tangible and identified intangible assets acquired based on estimated fair values. Above-market and below-market in-place lease values are recorded based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) the Company’s estimated fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease. Above-market lease values are amortized as a reduction of rental revenues (or rental expense for ground leases in which the Company is the lessee) over the remaining non-cancelable terms of the respective leases. Below-market lease values are amortized as an increase to rental revenues (or rental expense for ground leases in which the Company is the lessee) over the remaining non-cancelable terms of the respective leases, including any fixed-rate renewal periods that are probable of being exercised. For the Company’s below-market lease and in-place lease intangibles remaining at December 31, 2017 and 2016 , the Company assumed fixed rate renewals for the in-place leases deemed to be below market and include the assumed renewals in the calculation of intangible asset values and related amortization period. Intangible assets also include amounts representing the value of tenant relationships and in-place leases based on the Company’s evaluation of each tenant’s lease and its overall relationship with the respective tenant. The Company estimates the cost to execute leases with terms similar to in-place leases, including leasing commissions, legal and other related expenses. This intangible asset is amortized to expense over the remaining term of the respective lease. The Company’s estimates of value are made using methods similar to those used by independent appraisers or by using independent appraisals. Factors considered by the Company in this analysis include an estimate of the carrying costs during the expected lease-up periods, current market conditions and costs to execute similar leases. In estimating carrying costs, the Company includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the expected lease-up periods, which primarily range from three to twelve months. The Company also considers information obtained about each property as a result of its pre-acquisition due diligence, marketing and leasing activities in estimating the fair value of the tangible and intangible assets acquired. The Company also uses the information obtained as a result of its pre-acquisition due diligence in considering any conditional asset retirement obligations, and when necessary, will record a conditional asset retirement obligation as part of its purchase price. The value of in-place leases is amortized over the remaining non-cancelable term of the respective leases and any fixed-rate renewal periods deemed probable. The Company considers whether there is a value associated with a tenant relationship intangible asset. However, based on the nature of the assets typically acquired, it is rare for there to be a value assigned to this intangible asset. In the event a lease is terminated, the unamortized portion of each related intangible is charged to income or expense, as applicable.
Cash and Equivalents	Cash and Equivalents The Company considers all highly liquid instruments purchased with a maturity of three months or less to be cash equivalents. Cash equivalents are stated at cost, which approximates market value. The Company maintains operating cash and reserves for replacement balances in financial institutions which, from time to time, may exceed federally insured limits. The Company periodically assesses the financial condition of these institutions and believes the risk of loss is minimal. Cash flows associated with items intended as hedges of identifiable transactions or events are classified in the same category as the cash flows from the items being hedged. Cash flows from derivatives not designated as cash flow or fair value hedges are generally classified in the investing section in the Consolidated Statements of Cash Flows. Cash flows associated with lease procurement costs are classified as investing activities and consist primarily of lease commissions and related legal fees associated with procuring first generation tenants under long-term lease agreements for office buildings, regional malls or specialty retail centers. The Company primarily incurs these costs during the development phase of the project and they are integral to starting construction and ultimately completing the project. Management views these lease procurement costs as part of the initial investment to obtain long-term cash flow.
Restricted Cash	Restricted Cash Restricted cash represents amounts for debt service payments, taxes and insurance, collateral, security deposits, capital replacement, improvement and operating reserves, bond funds, and development and construction escrows.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts Allowances against notes and accounts receivables are based on management’s estimate of amounts that ultimately will not be realized from cash receipts or any applicable collateral. The Company’s notes receivable are evaluated individually for allowance purposes. As of December 31, 2017 , each of the Company’s notes receivables is performing and we expect to collect amounts as they come due, and, as such, interest income on the notes receivables is accrued as earned. If the estimate of expected future cash flows does not accurately reflect actual events, the allowance may be over or understated. Management exercises judgment in establishing these allowances and considers payment history and current credit status in developing these estimates. The Company also maintains an allowance for receivables arising from the straight-lining of rents.This receivable arises from earnings recognized in excess of amounts currently due under lease agreements. The allowance against the straight-line rent receivable is based on historical experience with early lease terminations as well as specific review of significant tenants and tenants having known financial difficulties. There is a risk the estimate of the expected activity of current tenants may not accurately reflect future events. If the estimate does not accurately reflect future tenant vacancies, the allowance for straight-line rent receivable may be over or understated.
Investments in Unconsolidated Entities	Investments in Unconsolidated Entities Investments in unconsolidated entities include investments in and advances to unconsolidated entities and cash distributions and losses in excess of investments in unconsolidated entities the Company does not control and/or is not deemed to be the primary beneficiary. The Company accounts for its investments in unconsolidated entities using the equity method of accounting whereby the cost of an investment is adjusted for the Company’s share of income or loss from the date of acquisition, increased for equity contributions made and reduced by distributions received. The income or loss for each unconsolidated entity is allocated in accordance with the provisions of the applicable operating agreements, including distribution priorities, which may change upon the achievement of certain return thresholds and may differ from the legal ownership interest held. Differences between the Company’s carrying value of its investment in unconsolidated entities and the Company’s underlying equity of such unconsolidated entities are amortized over the respective lives of the underlying assets or liabilities, as applicable. Certain investments in unconsolidated entities’ share of cumulative allocated losses and cash distributions received exceeds its cumulative allocated share of income and equity contributions. As a result, the carrying value of certain investments in unconsolidated entities is negative, based on the Company’s ongoing potential funding requirements. Unconsolidated entities with negative carrying values are included in cash distributions and losses in excess of investments in unconsolidated entities in the Consolidated Balance Sheets. The Company may provide funding in excess of its legal ownership. These fundings are typically interest-bearing or entitle the Company to a preference on and of such advances of property cash flows and are included in investments in and advances to unconsolidated entities.
Other Assets	Other Assets Other assets include costs incurred with obtaining the revolving credit facility financing, which are amortized over the life of the related facility and costs incurred with leasing space to tenants, which are amortized using the straight-line method over the terms of the related leases.
Intangible Assets	Intangible Assets Upon an acquisition of a rental property, the Company records intangible assets at their estimated fair value separate and apart from goodwill. The Company amortizes identified intangible assets with finite lives on a straight-line basis over the period the assets are expected to contribute directly or indirectly to the future cash flows of the acquired property. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate their carrying amount may not be recoverable. An impairment loss is recognized if the carrying amount of an intangible asset is not recoverable and its carrying amount exceeds its estimated fair value.
Derivatives Instruments and Hedging Activities	Derivative Instruments and Hedging Activities Derivatives are recorded at fair value. Accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and whether it meets the hedge accounting requirements. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Hedge accounting generally provides for the matching of gain or loss recognition on the instrument with the recognition of the change in the fair value of the hedged asset or liability attributable to the hedged risk (in a fair value hedge) or the earnings effect of the hedged forecasted transactions (in a cash flow hedge). The Company may enter into derivative contracts intended to economically hedge certain interest rate risk, even though the contracts do not qualify for or the Company has elected not to apply hedge accounting.
Noncontrolling Interest	Noncontrolling Interest Interests held by partners in consolidated entities are reflected in noncontrolling interest, which represents the noncontrolling interests’ share of the underlying net assets of the Company’s consolidated subsidiaries. Noncontrolling interest that is not redeemable is reported in the equity section of the Consolidated Balance Sheets. During the year ended December 31, 2017 , the Company exercised a promote option in the Arizona State Retirement System joint venture agreement, whereby the Company increased its ownership in the joint venture from 25.00% to 29.63% , as a result of the joint venture’s cumulative financial performance and estimated value creation. The non-cash transaction resulted in a decrease to noncontrolling interest and a corresponding increase to additional paid-in capital of $10,931,000 . The Company owned an equity interest in Barclays Center arena and the Nets through the Company’s consolidated subsidiary Nets Sports & Entertainment (“NS&E”). During the year ended December 31, 2016, subsequent to the sale of Barclays Center and the Nets, the Company purchased NS&E’s partners’ interest for $38,951,000 . This cash payment together with the partners’ historical noncontrolling interest debit balance resulted in a decrease to additional paid-in capital as reflected on the Consolidated Statement of Equity.
Reacquired Stock	Reacquired Stock Effective December 31, 2015, the Company accounts for purchases of capital stock consistent with Maryland law, which does not contemplate treasury stock. Any capital stock reacquired for any purpose is recorded as a reduction of Class A common stock (at $.01 par value per share) and a decrease in additional paid-in capital.
Recognition of Revenues	Recognition of Revenues Rental – Lease terms in office buildings, retail centers and certain parking facilities generally range from 1 to 30 years, excluding leases with certain anchor tenants, which typically are longer. Minimum rents are recognized on a straight-line basis over the non-cancelable term of the lease, which include the effects of rent steps and rent abatements under the leases. Overage rents are recognized after sales thresholds have been achieved. Apartment lease terms are generally one year. Tenant Recoveries – Reimbursements from office and retail tenants for common area maintenance, taxes, insurance and other property operating expenses as defined in the lease agreements are recognized in the period the applicable costs are incurred. Service and Management Fees – Management, leasing, finance, development and other service fee revenue is recognized in the period in which the services are performed. Revenues and profit on long-term fixed-price contracts are recorded using the percentage-of-completion method. Revenues on reimbursable cost-plus fee contracts are recorded in the amount of the accrued reimbursable costs plus proportionate fees at the time the costs are incurred. Parking and Other – Revenues derived from monthly and transient tenant parking and other revenue is recognized in the period the services are performed. Arena (sold in January 2016 and reported in discontinued operations) – The Arena naming rights agreement commenced with the opening of the Arena, had a 20 year term and was subject to certain extension rights. Arena naming rights revenue was recognized on a straight-line basis over the term of the agreement. Arena founding partner and sponsor agreements entitle the parties to certain sponsorship, promotional, media, hospitality and other rights and entitlements. These agreements expired at various terms ranging from one to seven years and revenue was recognized on a straight-line basis over the term of the agreements. Arena suite licenses entitle the licensee to the use of a luxury suite in the Arena. The terms of the suite license agreements ranged from one to seven years. Revenue was recognized on a straight-line basis over the term of the agreements. Ticketing fee revenue was based on the Arena’s share of ticket sale fees in accordance with an agreement with Ticketmaster. Revenue from ticketing fees was deferred and recognized upon settlement of the related event. Land Sales – Sales of land to residential, commercial and industrial customers, primarily at the Company’s Stapleton project, and sales of commercial and residential outlots adjacent to the Company’s operating property portfolio are recognized at closing or upon completion of all conditions precedent to the sales contract (whichever is later). Military Housing (sold in February 2016) – Property management and asset management fees were earned based on a contractual percentage of the annual net rental income and annual operating income, respectively, generated by the military housing projects as defined in the agreements. Additional property management incentive fees were recognized based upon successful completion of criteria set forth in the property management agreements. Development fees were earned based on a contractual percentage of the actual development costs incurred. Additional development incentive fees were recognized based upon successful completion of criteria, such as incentives to realize development cost savings, encourage small and local business participation, comply with specified safety standards and other project management incentives as specified in the development agreements. Construction management fees were earned based on a contractual percentage of the actual construction costs incurred. Additional construction incentive fees were recognized based upon successful completion of certain criteria as set forth in the construction contracts.
Real Estate Sales and Assets Held for Sale	Real Estate Sales and Assets Held for Sale The specific timing of a sale transaction and recognition of profit is measured against various criteria in the real estate sales accounting guidance covering the terms of the transaction and any continuing involvement in the form of management or financial assistance associated with the property. If the sales criteria are not met, the Company defers gain recognition and accounts for the transaction by applying the deposit, finance, installment or cost recovery methods, as appropriate. The determination of when an asset qualifies as held for sale continues to require significant judgment. The Company considers various factors when evaluating whether an asset qualifies as held for sale including, among others, whether the potential sale is approved by management, the status of any marketing efforts, interest from potential buyers, the status of any sale negotiations and the probability of whether the asset will be sold in twelve months. Each potential sale is evaluated based on its separate facts and circumstances.
Recognition of Expenses	Recognition of Expenses Property Operating and Management – Expenses incurred at the operating property level and general business unit expenses, including non-capitalizable development costs and management and service company expenses, are recognized as incurred. Real Estate Taxes – Real estate taxes on operating properties are recognized over the applicable tax period. Real estate taxes during active development and construction are capitalized as a project cost. Ground Rent – Ground lease expense is recognized using the straight-line method over the non-cancelable lease term. Participation payments triggered by defined events within the respective lease agreements such as refinancings, sales or other capital transactions are expensed when incurred. Ground rent during active development and construction is capitalized as a project cost. Arena Operating (sold in January 2016 and reported in discontinued operations) – Operating expenses related to the Arena were recognized as incurred. Cost of Land Sales – Cost of land associated with land sales is recognized in the same period as the respective revenue from the sale qualifies for recognition. Military Housing (sold in February 2016) – Operating expenses related to the Military Housing were recognized as incurred. Corporate General and Administrative – Expenses related to the Company’s Corporate segment are recognized as incurred.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation cost is measured at the date of grant and is based on the fair value of the equity award. The fair value of stock options is computed using the Black-Scholes option pricing model, which incorporates assumptions for risk-free rate, expected volatility, dividend yield, and expected life of the options. The fair value of restricted stock is equal to the closing price of the stock on the date of grant. The fair value cost of stock options and restricted stock, as adjusted for estimated forfeitures, is recognized over the requisite service period of the grantee using the straight-line attribution method. Cost recognition is accelerated if the grantee is retirement-eligible (as defined in the 1994 Stock Plan, as amended) or becomes retirement-eligible before the end of the nominal vesting period. The cost is recognized immediately if the grantee is retirement-eligible at the date of grant or on a straight-line basis over the period ending with the first anniversary from the date of grant when the individual becomes retirement-eligible. The fair value of performance shares that do not have a market condition is equal to the closing price of the underlying stock on the date of grant. The fair value cost is recognized on a straight-line basis over the requisite service period if it is probable the performance goals will be achieved. The fair value of performance shares that have a market condition is computed using a Monte Carlo simulation. The fair value cost is recognized over the requisite service period if the requisite service is rendered, even if the market condition is never satisfied. Cash flows resulting from the tax benefits from tax deductions in excess of the compensation cost recognized for those options or shares (excess tax benefits) are classified as operating cash flows in the Consolidated Statements of Cash Flows. The Company records excess tax benefits only if the excess tax deductions reduce taxes payable computed on a with-and-without basis. There were no excess tax benefits classified as financing cash flows for the years ended December 31, 2017, 2016 and 2015 .
Depreciation and Amortization	Depreciation and Amortization Depreciation and amortization is generally computed using the straight-line method over the estimated useful life of the asset. The estimated useful lives of buildings and certain first generation tenant allowances considered by management as a component of the building are 30 to 50 years. Subsequent tenant improvements and those first generation tenant allowances not considered a component of the building are amortized over the lesser of the estimated remaining useful life of the asset or the term of the lease. This estimated life is based on the length of time the asset is expected to generate positive operating cash flows. Actual events and circumstances can cause the life of the building and tenant improvement to be different than the estimates made. Additionally, lease terminations can affect the economic life of the tenant improvements.
Cost Capitalization	Cost Capitalization Major improvements and tenant improvements determined to be Company assets are capitalized and expensed through depreciation charges. Tenant improvements qualifying as lease inducements are capitalized into other assets and amortized as a reduction of rental revenues over the term of the tenant’s lease. Repairs, maintenance and minor improvements are expensed as incurred. A variety of costs are incurred in the development and leasing of properties. After determination is made to capitalize a cost, it is allocated to the specific component of the benefited project. Determination of when a development project is substantially complete and when capitalization must cease involves judgment. The Company’s capitalization policy on development properties is based on accounting guidance for the capitalization of interest cost and accounting guidance for costs and the initial rental operations of real estate properties. The costs of land and buildings under development include specifically identifiable costs. The capitalized costs include pre-construction costs essential to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. The Company considers a construction project as substantially complete and held available for occupancy upon the completion of tenant improvements, but no later than one year from cessation of major construction activity. The Company ceases capitalization on any portion substantially completed and occupied or held available for occupancy, and capitalizes only those costs associated with the portion under construction. Costs and accumulated depreciation applicable to assets retired or sold are removed from the respective accounts and any resulting gains or losses are reported in the Consolidated Statements of Operations.
Write-offs of Abandoned Development Projects and Demolition Costs	Write-offs of Abandoned Development Projects and Demolition Costs On a quarterly basis, the Company reviews each project under development to determine whether it is probable the project will be developed. If management determines the project will not be developed, its project costs and other related expenses are written off as an abandoned development project cost. The Company abandons projects under development for a number of reasons, including, but not limited to, changes in local market conditions, increases in construction or financing costs or third party challenges related to entitlements or public financing. In addition, costs expensed to demolish existing structures, if any, are included in these amounts.
Impairment of Real Estate	Impairment of Real Estate The Company reviews its real estate for impairment whenever events or changes indicate its carrying value may not be recoverable. Impairment indicators include, but are not limited to, significant decreases in property net operating income, significant decreases in occupancy rates, the physical condition of the property and general economic conditions. A property’s value is impaired if the aggregate future cash flows (undiscounted and without interest charges) to be generated are less than the carrying value of the property. In addition, the undiscounted cash flows may consider a probability-weighted cash flow estimation approach when alternative courses of action to recover the carrying amount of a long-lived asset are under consideration or a range is estimated at the balance sheet date. Significant estimates are made in the determination of future undiscounted cash flows including future net operating income, estimated hold periods, probability of alternative courses of action, risk of foreclosure and estimated cash proceeds received upon disposition of the asset. To the extent an impairment has occurred, the loss will be measured as the excess of the carrying amount of the property over the estimated fair value of the property. Determining fair value of real estate involves significant judgments and estimates including timing and amounts of expected cash flows, discount rates, capitalization rates and comparable sales data, which are considered Level 3 inputs. Changes to these estimates could affect whether or not an impairment charge would be required and/or the amount of impairment charges recognized.
Impairment of Unconsolidated Entities	Impairment of Unconsolidated Entities The Company reviews its portfolio of unconsolidated entities for other-than-temporary impairments whenever events or changes indicate its carrying value in the investments may be in excess of fair value. A loss in value of an equity method investment which is other-than-temporary is recognized as an impairment of unconsolidated entities. This determination is based upon the length of time elapsed, severity of decline, possible recovery period and other relevant facts. Determining fair value of a real estate investment and whether or not a loss is other-than-temporary involves significant judgments and estimates. Examples of these estimates include timing and amounts of expected cash flows, discount rates, capitalization rates and comparable sales data, which are considered Level 3 inputs. Changes to these estimates could affect whether or not an impairment charge would be required and/or the amount of impairment charges recognized.
Historic and New Market Tax Credit Entities	Historic and New Market Tax Credit Entities The Company invests in properties that have received, or the Company believes are entitled to receive, historic preservation tax credits on qualifying expenditures under Internal Revenue Code (“IRC”) section 47 and new market tax credits on qualifying investments in designated community development entities (“CDEs”) under IRC section 45D, as well as various state credit programs, including participation in the New York State Brownfield Tax Credit Program, which entitles the members to tax credits based on qualified expenditures at the time those qualified expenditures are placed in service. The Company typically enters into these investments with sophisticated financial investors. In exchange for the financial investors’ initial contribution into the investment, the financial investor is entitled to substantially all of the benefits derived from the tax credit. Typically, these arrangements have put/call provisions (which range up to seven years) whereby the Company may be obligated (or entitled) to repurchase the financial investors’ interest. The Company has consolidated each of these entities in its consolidated financial statements and has included these investor contributions in accounts payable, accrued expenses and other liabilities. The Company guarantees to the financial investor that in the event of a subsequent recapture by a taxing authority due to the Company’s noncompliance with applicable tax credit guidelines, it will indemnify the financial investor for any recaptured tax credits. The Company initially records a liability for the cash received from the financial investor. The Company generally records income upon completion and certification of the qualifying development expenditures for historic preservation tax credits and upon certification of the qualifying investments in designated CDEs for new market tax credits, resulting in an adjustment of the liability at each balance sheet date to the amount that would be paid to the financial investor based upon the tax credit compliance regulations, which range from 0 to 7 years . Income related to the sale of tax credits is recorded in interest and other income.
Income Taxes	Income Taxes To qualify as a REIT, the Company is required to meet a number of organizational and operational requirements, including distributing as a dividend to stockholders at least 90% of the Company’s annual REIT taxable income, computed without regard to the dividends paid deduction and the Company’s net capital gains. As a REIT, the Company will generally not be subject to federal income taxes on its income and gains that are distributed to its stockholders. The states in which the Company operates follow rules similar to the federal rules with respect to the taxation of REITs. If the Company fails to qualify as a REIT in any taxable year, the Company will be subject to federal and state income taxes at regular corporate rates. In addition, the Company may not be able to requalify as a REIT for the four subsequent taxable years. However, certain activities will be conducted in TRSs and will continue to be subject to federal income taxes. In addition, the Company will be subject to corporate income taxes related to assets sold during the 5 year period following the date of conversion (ending December 31, 2020), to the extent such assets had a built-in gain on the date of conversion. This gain can be offset against any remaining federal net operating loss carryforwards. Furthermore, the Company does not intend to dispose of any assets after the REIT conversion within the specified period, unless net operating losses or various tax planning strategies, including Internal Revenue Code Section 1031 like-kind exchanges or other deferred tax structures are available, to mitigate the built-in gain tax liability. During the three months ended December 31, 2015, all remaining contingencies to convert to a REIT were satisfied, including stockholder approval on October 20, 2015. As a result, the Company recorded a $588,607,000 one-time reversal of its net deferred tax liability related to its qualified REIT investments. Deferred tax assets and liabilities related to the Company’s TRSs were not reversed but included an adjustment to the reserve valuation allowance required as of December 31, 2015. See Note V – Income Taxes for additional information. Prior to the conversion to a REIT and subsequent to the REIT conversion as it relates to the Company’s TRSs, deferred tax assets and liabilities are recorded to reflect the expected tax consequences on future years attributable to temporary differences between the financial statement carrying amounts and the tax basis of existing assets and liabilities. At December 31, 2015, the Company had recognized the benefit of a portion of its tax loss carryforward, which were offset against the gains on sales of our interests in military housing entities, Barclays Center and the Nets during the year ended December 31, 2016. The Company records valuation allowances against deferred tax assets if it is more likely than not a portion or all of the deferred tax asset will not be realized. The Company’s financial statements reflect the expected future tax consequences of a tax position if that tax position is more likely than not of being sustained upon examination, presuming the taxing authorities have full knowledge of the position and all relevant facts. The Company records interest and penalties related to uncertain income tax positions as a component of income tax expense.
Earnings Per Share	Earnings Per Share The Company’s restricted stock is considered a participating security pursuant to the two-class method for computing basic earnings per share (“EPS”). The 2006 Class A Common Units (“2006 Units”) issued in exchange for Bruce C. Ratner’s noncontrolling interests in the Forest City Ratner Company portfolio in November 2006, which are reflected as noncontrolling interests in the Consolidated Balance Sheets, are considered convertible participating securities as they are entitled to participate in dividends paid to the Company’s common stockholders. The 2006 Units are included in the computation of basic EPS using the two-class method and are included in the computation of diluted EPS using the if-converted method. The Class A common stock issuable in connection with a conversion of the Convertible Senior Notes due 2016, Convertible Senior Notes due 2018 and Convertible Senior Notes due 2020 are included in the computation of diluted EPS using the if-converted method for the applicable period such notes were outstanding.

Summary of Significant Accoun43

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Components of Accumulated Other Comprehensive Income (Loss)	The following table summarizes the components of accumulated other comprehensive loss (“accumulated OCI”): December 31, 2017 2016 2015 (in thousands) Unrealized losses on foreign currency translation $ — $ — $ 95 Unrealized losses on interest rate derivative contracts (1) 8,612 14,473 67,888 8,612 14,473 67,983 Noncontrolling interest (49 ) (63 ) (78 ) Accumulated other comprehensive loss $ 8,563 $ 14,410 $ 67,905
Schedule of Changes of Accumulated Other Comprehensive Income by Component	The following table summarizes the changes, net of tax and noncontrolling interest, of accumulated OCI by component: Foreign Currency Translation Interest Rate Contracts Total (in thousands) Balance, January 1, 2015 $ (84 ) $ (58,762 ) $ (58,846 ) Gain (loss) recognized in accumulated OCI 24 (6,445 ) (6,421 ) Loss reclassified from accumulated OCI — 29,013 29,013 One-time adjustment to deferred taxes on OCI related to REIT conversion (3) (35 ) (31,616 ) (31,651 ) Total other comprehensive income (loss) (11 ) (9,048 ) (9,059 ) Balance, December 31, 2015 $ (95 ) $ (67,810 ) $ (67,905 ) Gain (loss) recognized in accumulated OCI 95 (9,414 ) (9,319 ) Loss reclassified from accumulated OCI — 62,814 62,814 Total other comprehensive income 95 53,400 53,495 Balance, December 31, 2016 $ — $ (14,410 ) $ (14,410 ) Gain recognized in accumulated OCI — 476 476 Loss reclassified from accumulated OCI — 5,371 5,371 Total other comprehensive income — 5,847 5,847 Balance, December 31, 2017 $ — $ (8,563 ) $ (8,563 )
Losses reclassified from Accumulated Other Comprehensive Income	The following table summarizes losses reclassified from accumulated OCI and their location on the Consolidated Statements of Operations: Accumulated OCI Components Loss Reclassified from Accumulated OCI Location on Consolidated Statements of Operations (in thousands) Year Ended December 31, 2017 Interest rate contracts $ 2,817 Interest expense Interest rate contracts 2,568 Earnings from unconsolidated entities 5,385 Total before income tax and noncontrolling interest (14 ) Noncontrolling interest $ 5,371 Loss reclassified from accumulated OCI Year Ended December 31, 2016 Interest rate contracts $ 34,889 Interest expense Interest rate contracts 24,635 Reclassification adjustment for interest rate swap breakage fee Interest rate contracts 113 Net gain (loss) on disposition of full or partial interest in rental properties, net of tax Interest rate contracts 3,192 Earnings from unconsolidated entities 62,829 Total before income tax and noncontrolling interest (15 ) Noncontrolling interest $ 62,814 Loss reclassified from accumulated OCI Year Ended December 31, 2015 Interest rate contracts $ 37,852 Interest expense Interest rate contracts (900 ) Gain on change in control of interests Interest rate contracts 3,722 Earnings from unconsolidated entities 40,674 Total before income tax and noncontrolling interest (11,645 ) Income tax benefit (16 ) Noncontrolling interest $ 29,013 Loss reclassified from accumulated OCI
Summary of components of Organizational Transformation and Termination Benefits	Years Ended December 31, 2017 2016 2015 (in thousands) Termination benefits $ 17,728 $ 13,032 $ 17,980 Strategic alternative costs 13,190 — — Shareholder activism costs 3,477 3,493 — Reorganization costs — 14,320 19,050 REIT conversion costs — 863 11,095 Total $ 34,395 $ 31,708 $ 48,125
Schedule of Accrued Severance	The following table summarizes the activity in the accrued severance balance for termination benefits: Total (in thousands) Accrued severance benefits at December 31, 2014 $ 4,982 Termination benefits expense 17,980 Payments (6,624 ) Accrued severance benefits at December 31, 2015 $ 16,338 Termination benefits expense 13,032 Payments (19,401 ) Accrued severance benefits at December 31, 2016 $ 9,969 Termination benefits expense 17,728 Payments (13,723 ) Accrued severance benefits at December 31, 2017 $ 13,974
Supplemental Non-Cash Disclosures	Years Ended December 31, 2017 2016 2015 (in thousands) Non-cash changes to balance sheet - Investing activities Projects under construction and development $ (63,573 ) $ (61,745 ) $ 55,484 Completed rental properties (239,367 ) (1,257,606 ) 825,582 Restricted cash 8,670 (13,466 ) 8,969 Notes receivable 39,435 277,050 — Investments in and advances to affiliates - due to dispositions or change in control 603 149,664 81,978 Investments in and advances to affiliates - other activity (716 ) 3,228 20,852 Total non-cash effect on investing activities $ (254,948 ) $ (902,875 ) $ 992,865 Non-cash changes to balance sheet - Financing activities Nonrecourse mortgage debt and notes payable, net $ (194,116 ) $ (935,479 ) $ 433,499 Convertible senior debt, net (1 ) (125 ) (424,433 ) Class A common stock 59 — (76,823 ) Additional paid-in capital 51,080 (14,755 ) 531,246 Treasury stock — — 22,434 Redeemable noncontrolling interest — (159,202 ) — Noncontrolling interest (54,573 ) 19,087 (53,426 ) Total non-cash effect on financing activities $ (197,551 ) $ (1,090,474 ) $ 432,497

Accounts Receivable, Net (Table

Accounts Receivable, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Components of Accounts Receivable, Net	The following table summarizes the components of accounts receivable, net: December 31, 2017 2016 (in thousands) Straight-line rent - tenants $ 110,201 $ 119,366 Accounts receivable - tenants 11,206 13,263 Alternative minimum tax (“AMT”) credit receivable 28,100 — Other 78,912 81,258 228,419 213,887 Allowance for doubtful accounts (3,397 ) (5,324 ) Total $ 225,022 $ 208,563

Notes Receivable (Tables)

Notes Receivable (Tables)	12 Months Ended
	Dec. 31, 2017
Notes Receivable [Abstract]
Summary of Notes Receivable	The following table summarizes the components of interest bearing notes receivable: December 31, Weighted Average Interest Rate 2017 2016 Date of Maturity (in thousands) Stapleton advances $ 128,676 $ 141,034 Various 8.53% The Nets sale 125,100 125,100 January 2021 4.50% Barclays Center sale 92,600 92,600 January 2019 4.50% QIC 36,935 — April 2019 4.25% Other 15,474 24,429 Various 4.82% Total $ 398,785 $ 383,163

Investments in Unconsolidated46

Investments in Unconsolidated Entities (Tables)	12 Months Ended
	Dec. 31, 2017
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]
Reconciliation of Members' and Partners' Equity to the Company's Carrying Value	The following table is a reconciliation of members’ and partners’ equity to the Company’s carrying value: December 31, 2017 2016 (in thousands) Total members’ and partners’ equity $ 1,478,172 $ 1,428,242 Equity of other members and partners 1,021,051 998,199 Company’s net investment in unconsolidated entities 457,121 430,043 Basis differences (1) (25,838 ) (16,356 ) Advances to and on behalf of affiliates (4,803 ) 500 Total Investments in Unconsolidated Entities, net $ 426,480 $ 414,187 Assets - Investments in and advances to unconsolidated entities $ 550,362 $ 564,779 Liabilities - Cash distributions and losses in excess of investments in unconsolidated entities (123,882 ) (150,592 ) Total Investments in Unconsolidated Entities, net $ 426,480 $ 414,187 (1) Represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the equity method venture level, which is typically amortized over the life of the related assets or liabilities. Basis differences relate to certain acquisition, transaction and other costs, as well as other-than-temporary impairments not reflected at the equity method venture level.
Summarized Financial Information for the Equity Method Investments	The following table presents summarized financial information for equity method investments: (Combined 100%) December 31, 2017 2016 (in thousands) Balance Sheets: Real Estate Completed rental properties $ 6,577,155 $ 6,303,559 Projects under construction and development 1,375,381 1,817,074 Land inventory 36,682 51,142 Total Real Estate 7,989,218 8,171,775 Less accumulated depreciation (1,462,177 ) (1,525,369 ) Real Estate, net 6,527,041 6,646,406 Cash and equivalents 127,877 144,790 Other restricted cash 187,293 230,163 Other assets 482,308 541,145 Total Assets $ 7,324,519 $ 7,562,504 Nonrecourse mortgage debt and notes payable, net $ 5,425,032 $ 5,635,343 Other liabilities 421,315 498,919 Members’ and partners’ equity 1,478,172 1,428,242 Total Liabilities and Members’ and Partners’ Equity $ 7,324,519 $ 7,562,504 (Combined 100%) Years Ended December 31, 2017 2016 2015 (in thousands) Operations: Revenues $ 958,696 $ 809,209 $ 1,100,094 Operating expenses (494,114 ) (343,036 ) (491,804 ) Depreciation and amortization (198,706 ) (225,712 ) (244,126 ) Interest and other income 17,637 16,297 19,721 Net gain (loss) on disposition of full or partial interest in rental properties 49,250 (24,475 ) — Interest expense including extinguishment of debt (211,056 ) (216,198 ) (314,332 ) Earnings from continuing operations $ 121,707 $ 16,085 $ 69,553 Discontinued operations: Operating loss from rental properties — (7,561 ) (64,766 ) Discontinued operations subtotal — (7,561 ) (64,766 ) Net earnings (loss) $ 121,707 $ 8,524 $ 4,787 Company’s portion of net earnings 25,163 29,701 22,313 Impairment of investments in unconsolidated entities (10,600 ) (306,400 ) (13,844 ) Company’s portion of gain on disposition of full or partial interest in rental properties 32,316 13,166 — Net gain on disposition of full or partial interest in equity method investments 77,905 — 20,293 Net earnings from unconsolidated entities $ 124,784 $ (263,533 ) $ 28,762
Summary of the Gain (Loss) on the Disposition of Unconsolidated Entities	The following table summarizes gains and losses on the disposition or partial disposition of unconsolidated entities which are included in equity from unconsolidated entities: Years Ended December 31, 2017 2016 2015 (in thousands) Net gain (loss) on disposition of full or partial interest in rental properties: Federally assisted housing apartment communities Various $ 27,942 $ — $ — Specialty Retail Centers: Shops at Bruckner Boulevard Bronx, New York 21,308 — — Steinway Street Theaters Queens, New York — 29,489 — Mesa del Sol (Land Inventory) (1) Albuquerque, New Mexico — (53,964 ) — Total gain (loss) on disposition of full or partial interest in rental properties $ 49,250 $ (24,475 ) $ — Company’s portion of gain on disposition of full or partial interest in rental properties $ 32,316 $ 13,166 $ — Net gain (loss) on disposition of full or partial interest in equity method investments: Apartment Communities: Federally assisted housing Various $ 49,800 $ — $ — Newport Landing Coventry Township, Ohio — — 5,765 Eaton Ridge Sagamore Hills, Ohio — — 4,745 Arbor Glen Twinsburg, Ohio — — 3,422 Parkwood Village Brunswick, Ohio — — 2,817 Sutton Landing Brimfield, Ohio — — 2,535 South Bay Galleria (Regional Mall) Redondo Beach, CA 28,180 — — Suburban Cleveland office properties Beachwood, OH 1,437 — — Other (1,512 ) — 1,009 Total gain on disposition of full or partial interest in equity method investments $ 77,905 $ — $ 20,293 (1) Represents the loss recorded at the joint venture level upon disposition of real estate. Prior to the year ended December 31, 2016, the Company impaired its investment in the joint venture and therefore was not allocated a material portion of this loss recorded at the joint venture level.

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Components of Other Assets	The following table summarizes the components of other assets: December 31, 2017 2016 (in thousands) Intangible assets, net $ 106,786 $ 134,562 Prepaid expenses and other deferred costs, net 75,839 73,987 Lease procurement costs, net 59,810 66,065 Total $ 242,435 $ 274,614
Schedule of Future Amortization Expense Related to Intangible Assets	The following table summarizes the estimated amortization expense related to intangible assets for the next five years: Years Ending December 31, (in thousands) 2018 $ 12,176 2019 11,569 2020 7,763 2021 4,460 2022 3,483

Nonrecourse Mortgage Debt and48

Nonrecourse Mortgage Debt and Notes Payable, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Nonrecourse Mortgage Debt and Notes Payable, Net [Abstract]
Summary of Nonrecourse Mortgage Debt and Notes Payable, Net	The following tables summarize nonrecourse mortgage debt and notes payable, net, which is collateralized solely by completed rental properties, projects under construction and development and undeveloped land: December 31, 2017 Operating Properties Projects under Construction and Development Total Total Weighted Average Rate (dollars in thousands) Fixed $ 1,615,592 $ 40,165 $ 1,655,757 4.27 % Variable Taxable 680,907 — 680,907 3.59 % Tax-Exempt 648,809 12,888 661,697 2.58 % $ 2,945,308 $ 53,053 $ 2,998,361 3.74 % December 31, 2016 Operating Properties Projects under Construction and Development Total Total Weighted Average Rate (dollars in thousands) Fixed $ 1,874,206 $ 68,855 $ 1,943,061 4.42 % Variable Taxable 508,449 70,222 578,671 2.96 % Tax-Exempt 599,101 — 599,101 1.68 % $ 2,981,756 $ 139,077 $ 3,120,833 3.62 %
Summary of Nonrecourse Mortgage Debt and Notes Payable, Net Maturities	The following table summarizes the nonrecourse mortgage debt and notes payable, net maturities as of December 31, 2017 : Years Ending December 31, (in thousands) 2018 $ 467,380 2019 480,819 2020 239,281 2021 195,128 2022 208,544 Thereafter 1,438,666 3,029,818 Net unamortized mortgage procurement costs (31,457 ) Total $ 2,998,361

Revolving Credit Facility (Tabl

Revolving Credit Facility (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Available Credit on the Credit Facility	The following table summarizes the available credit on the Revolving Credit Facility: December 31, 2017 2016 (in thousands) Total available borrowings $ 600,000 $ 600,000 Less: Outstanding borrowings — — Letters of credit 36,439 44,215 Available credit $ 563,561 $ 555,785

Term Loan Facility, Net (Tables

Term Loan Facility, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Term Loan Facility, Net [Abstract]
Schedule of Debt [Table Text Block]	The following table summarizes the Term Loan Facility, net: December 31, 2017 2016 (in thousands) Total outstanding borrowings $ 335,000 $ 335,000 Net unamortized debt procurement costs (1,332 ) (1,732 ) Total $ 333,668 $ 333,268 The following table summarizes the convertible senior debt, net: December 31, 2017 2016 (in thousands) 4.250% Notes due 2018 $ 73,215 $ 73,216 3.625% Notes due 2020 40,021 40,021 113,236 113,237 Net unamortized debt procurement costs (599 ) (1,056 ) Total $ 112,637 $ 112,181

Convertible Senior Debt (Tables

Convertible Senior Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Convertible Senior Debt	The following table summarizes the Term Loan Facility, net: December 31, 2017 2016 (in thousands) Total outstanding borrowings $ 335,000 $ 335,000 Net unamortized debt procurement costs (1,332 ) (1,732 ) Total $ 333,668 $ 333,268 The following table summarizes the convertible senior debt, net: December 31, 2017 2016 (in thousands) 4.250% Notes due 2018 $ 73,215 $ 73,216 3.625% Notes due 2020 40,021 40,021 113,236 113,237 Net unamortized debt procurement costs (599 ) (1,056 ) Total $ 112,637 $ 112,181
Schedule of Debt Conversions	The following table summarizes the convertible senior debt transactions completed during the year ended December 31, 2016: Agreement Date Issuance Aggregate Principal Class A Common Shares Issued Cash Payments to Noteholders Loss on Extinguishment (in thousands, except share data) January 20, 2016 2016 Senior Notes $ 125 9,298 $ — $ 59 March 14, 2016 2018 Senior Notes 77,310 — 90,958 15,370 March 17, 2016 2018 Senior Notes 4,000 — 4,707 795 March 14, 2016 2020 Senior Notes 76,334 — 86,858 12,823 Total $ 157,769 9,298 $ 182,523 $ 29,047
Conversion Adjustments [Table Text Block]	The following table summarizes required adjustments to the Conversion Rate and approximate Conversion price of the 2018 Senior Notes triggered by the Company’s cash dividends: Effective Date Conversion Rate Conversion Price (in shares) June 10, 2016 46.6375 $ 21.44 June 9, 2017 47.2567 $ 21.16 December 20, 2017 47.8122 $ 20.92 The following table summarizes required adjustments to the Conversion Rate and approximate Conversion price of the 2020 Senior Notes triggered by the Company’s cash dividends: Effective Date Conversion Rate Conversion Price (in shares) June 10, 2016 41.7561 $ 23.95 June 9, 2017 42.3105 $ 23.63 December 20, 2017 42.8079 $ 23.36
Summary of Interest Incurred, Capitalized and Paid	The following table summarizes interest incurred, capitalized and paid on all forms of indebtedness (included in Notes F , G , H and I ): Years Ended December 31, 2017 2016 2015 (in thousands) Interest incurred $ 141,582 $ 170,080 $ 194,041 Interest capitalized (21,151 ) (38,639 ) (36,875 ) Net interest expense from continuing operations $ 120,431 $ 131,441 $ 157,166 Interest incurred from discontinued operations $ — $ 3,540 $ 40,125 Cash paid for interest (net of amount capitalized) $ 116,987 $ 130,766 $ 200,781

Derivative Instruments and He52

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments	The following table summarizes the fair values and location in the Consolidated Balance Sheets of all derivative instruments: Fair Value of Derivative Instruments December 31, 2017 Asset Derivatives (included in Other Assets) Liability Derivatives (included in Accounts Payable, Accrued Expenses and Other Liabilities) Current Notional Fair Value Current Notional Fair Value (in thousands) Derivatives Designated as Hedging Instruments Interest rate swaps $ 63,372 $ 1,129 $ 34,078 $ 863 TROR 369,021 3,862 236,015 652 Total $ 432,393 $ 4,991 $ 270,093 $ 1,515 Derivatives Not Designated as Hedging Instruments Interest rate caps $ 69,518 $ — $ — $ — TROR 100,466 4,107 36,280 11,330 Total $ 169,984 $ 4,107 $ 36,280 $ 11,330 December 31, 2016 Derivatives Designated as Hedging Instruments Interest rate swaps $ 64,248 $ 593 $ 34,666 $ 1,504 TROR 235,970 5,008 316,015 12,442 Total $ 300,218 $ 5,601 $ 350,681 $ 13,946 Derivatives Not Designated as Hedging Instruments Interest rate caps $ 69,518 $ — $ — $ — TROR 100,800 4,117 37,044 12,256 Total $ 170,318 $ 4,117 $ 37,044 $ 12,256
Gains and Losses Related to Derivative Instruments Designated as Cash Flow Hedges Included in Accumulated OCI	The following table summarizes the impact of gains and losses related to derivative instruments designated as cash flow hedges included in the accumulated OCI section of the Consolidated Balance Sheets and in equity in earnings and interest expense in the Consolidated Statements of Operations: Gain (Loss) Reclassified from Accumulated OCI Derivatives Designated as Cash Flow Hedging Instruments Gain (Loss) Recognized in OCI (Effective Portion) Location on Consolidated Statements of Operations Effective Amount Ineffective Amount (in thousands) Year Ended December 31, 2017 Interest rate caps and interest rate swaps $ 476 Interest expense $ (2,801 ) $ (16 ) Earnings from unconsolidated entities (2,568 ) — Total $ 476 $ (5,369 ) $ (16 ) Year Ended December 31, 2016 Interest rate caps and interest rate swaps $ (9,414 ) Interest expense $ (35,008 ) $ 119 Reclassification adjustment for interest rate swap breakage fee (24,635 ) — Net gain (loss) on disposition of full or partial interest in rental properties, net of tax (113 ) — Earnings from unconsolidated entities (3,192 ) — Total $ (9,414 ) $ (62,948 ) $ 119 Year Ended December 31, 2015 Interest rate caps and interest rate swaps $ (12,478 ) Interest expense $ (37,831 ) $ (21 ) Gain on change of control in interests 900 — Earnings from unconsolidated entities (3,721 ) (1 ) Total $ (12,478 ) $ (40,652 ) $ (22 )
Impact of Gains and Losses Related to Derivative Instruments Not Designated as Cash Flow Hedges	The following table summarizes the impact of gains and losses related to derivative instruments not designated as cash flow hedges in the Consolidated Statements of Operations: Net Gain (Loss) Recognized Years Ended December 31, 2017 2016 2015 (in thousands) Derivatives Designated as Fair Value Hedging Instruments TROR (1) $ 10,644 $ (4,624 ) $ 2,794 Derivatives Not Designated as Hedging Instruments Interest rate caps and interest rate swaps $ (45 ) $ (107 ) $ (157 ) TROR 916 (164 ) 5,266 Total $ 871 $ (271 ) $ 5,109 (1) The net gain (loss) recognized in interest expense from the change in fair value of the underlying TROR borrowings was $(10,644) , $4,624 and $(2,794) for the years ended December 31, 2017, 2016 and 2015 , respectively, offsetting the gain (loss) recognized on the TROR.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities and Redeemable Noncontrolling Interest Measured on a Recurring Basis	The following table summarizes information about financial assets and liabilities measured at fair value on a recurring basis, and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value: Fair Value Measurements December 31, 2017 Level 1 Level 2 Level 3 Total (in thousands) Interest rate swaps (assets) $ — $ 1,129 $ — $ 1,129 Interest rate swaps (liabilities) — (863 ) — (863 ) TROR (assets) — — 7,969 7,969 TROR (liabilities) — — (11,982 ) (11,982 ) Fair value adjustment to the borrowings subject to TROR — — (3,210 ) (3,210 ) Total $ — $ 266 $ (7,223 ) $ (6,957 ) December 31, 2016 Level 1 Level 2 Level 3 Total (in thousands) Interest rate swap (assets) $ — $ 593 $ — $ 593 Interest rate swaps (liabilities) — (1,504 ) — (1,504 ) TROR (assets) — — 9,125 9,125 TROR (liabilities) — — (24,698 ) (24,698 ) Fair value adjustment to the borrowings subject to TROR — — 7,434 7,434 Total $ — $ (911 ) $ (8,139 ) $ (9,050 )
Reconciliation of Financial Assets and Liabilities and Redeemable Noncontrolling Interest Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs	The following table presents a reconciliation of financial assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3): Net Fair value Total (in thousands) Balance, December 31, 2015 $ (10,785 ) $ 2,810 $ (7,975 ) Total realized and unrealized gains (losses): Included in earnings (4,788 ) 4,624 (164 ) Balance, December 31, 2016 $ (15,573 ) $ 7,434 $ (8,139 ) Total realized and unrealized gains (losses): Included in earnings 11,560 (10,644 ) 916 Balance, December 31, 2017 $ (4,013 ) $ (3,210 ) $ (7,223 )
Significant Unobservable Inputs Used to Estimate Fair Value of Financial Instruments	The following table presents quantitative information about the significant unobservable inputs used to estimate the fair value of financial instruments measured on a recurring basis as of December 31, 2017 : Quantitative Information about Level 3 Fair Value Measurements Fair Value December 31, 2017 Valuation Technique Unobservable Input Input Values (in thousands) TROR $ (4,013 ) Third party bond pricing Bond valuation 98.81 - 118.00 Fair value adjustment to the borrowings subject to TROR $ (3,210 ) Third party bond pricing Bond valuation 98.81 - 101.87
Schedule of Fair Value of Nonrecourse Mortgage Debt and Notes Payable, Bank Revolving Credit Facility and Senior and Subordinated Debt	The following table summarizes the fair value of nonrecourse mortgage debt and notes payable, net, including balances classified as held for sale (exclusive of the fair value of derivatives), term loan facility, net and convertible senior debt, net: December 31, 2017 December 31, 2016 Carrying Value Fair Value Carrying Value Fair Value (in thousands) Nonrecourse mortgage debt and notes payable, net $ 2,998,361 $ 2,995,559 $ 3,120,833 $ 3,105,587 Term loan facility, net 333,668 333,726 333,268 333,527 Convertible senior debt, net 112,637 130,942 112,181 122,795 Total $ 3,444,666 $ 3,460,227 $ 3,566,282 $ 3,561,909

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Completion Guarantees	The Company currently provides the following completion guarantees on its completed projects and projects under construction and development (including unconsolidated properties): Total Costs Percent Completed (Unaudited) (dollars in thousands) At December 31, 2017 Openings $ 2,029,900 93 % Under construction 615,800 48 % Total Real Estate $ 2,645,700 82 %

Dividends (Tables)

Dividends (Tables)	12 Months Ended
	Dec. 31, 2017
Dividends [Abstract]
Dividends Declared	The following table summarizes cash dividends declared by the Board of Directors on the Company’s common stock (in thousands, except per share data): Type Date Declared Record Date Payment Date Amount Per Share Total Cash Payment 2017 Quarterly November 29, 2017 December 20, 2017 December 29, 2017 $ 0.14 $ 37,344 Quarterly August 22, 2017 September 5, 2017 September 18, 2017 $ 0.14 $ 37,343 Quarterly May 17, 2017 June 9, 2017 June 23, 2017 $ 0.09 $ 23,482 Quarterly March 1, 2017 March 13, 2017 March 27, 2017 $ 0.09 $ 23,441 $ 0.46 $ 121,610 2016 Quarterly November 30, 2016 December 12, 2016 December 23, 2016 $ 0.06 $ 15,620 Quarterly August 18, 2016 September 2, 2016 September 16, 2016 $ 0.06 $ 15,621 Quarterly May 17, 2016 June 10, 2016 June 24, 2016 $ 0.06 $ 15,623 Quarterly February 18, 2016 March 4, 2016 March 18, 2016 $ 0.06 $ 15,596 E&P February 18, 2016 March 4, 2016 March 18, 2016 $ 0.10 $ 25,992 Total $ 0.34 $ 88,452
Tax treatment of Common Stock dividends [Table Text Block]	The following table summarizes the tax treatment of the Company’s Common Stock dividends for the years ended December 31, 2017 and 2016 : December 31, 2017 2016 Amount Per Share % Amount Per Share % Ordinary income $ 0.04 9.44 % $ 0.11 31.49 % Capital gain $ 0.42 90.56 % $ 0.23 68.51 % Total $ 0.46 100.00 % $ 0.34 100.00 %

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Minimum Future Rental Income	The following table summarizes the minimum future rental income to be received on non-cancelable operating leases of commercial properties that generally extend for periods of more than one year: Years Ending December 31, (in thousands) 2018 $ 343,765 2019 320,345 2020 298,282 2021 267,313 2022 247,632 Thereafter 1,129,277 $ 2,606,614
Minimum Fixed Rental Payments Under Long-term Leases	The following table summarizes the minimum fixed rental payments under long-term leases (over one year) in effect at December 31, 2017 : Years Ending December 31, (in thousands) 2018 $ 9,523 2019 10,899 2020 11,060 2021 11,180 2022 10,769 Thereafter 312,661 $ 366,092
Rent Expense	The following table summarizes rent expense: Years Ended December 31, 2017 2016 2015 (in thousands) Rent expense $ 16,659 $ 16,886 $ 14,032

Stock-Based Compensation (Tabl

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock-Based Compensation Costs and Related Deferred Income Tax Benefit	The following table summarizes stock-based compensation costs and related deferred income tax benefit recognized in the financial statements: Years Ended December 31, 2017 2016 2015 (in thousands) Stock option costs $ 590 $ 937 $ 1,314 Restricted stock costs 17,133 14,788 17,211 Performance share costs 9,161 9,738 13,310 Total stock-based compensation costs 26,884 25,463 31,835 Less amount capitalized into qualifying real estate projects (8,146 ) (5,661 ) (7,717 ) Amount charged to operating expenses 18,738 19,802 24,118 Depreciation expense on capitalized stock-based compensation 880 607 894 Total stock-based compensation expense $ 19,618 $ 20,409 $ 25,012 Deferred income tax benefit $ 511 $ 610 $ 9,629
Schedule of Stock Options Valuation Assumptions	The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions used for options granted during the respective years: Years Ended December 31, 2017 2016 2015 Risk-free interest rate 2.12 % 1.41 % 1.71 % Expected volatility 25.10 % 26.60 % 30.80 % Expected dividend yield 1.69 % 1.04 % 0.00 % Expected term (in years) 5.5 5.5 5.5
Schedule of Stock Options Activity	The following table summarizes stock option activity for the year ended December 31, 2017 : Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in months) Intrinsic Value (in thousands) Outstanding at January 1, 2017 2,545,031 $ 31.25 Granted 26,112 $ 21.83 Exercised (90,545 ) $ 16.54 Forfeited/expired (662,840 ) $ 64.77 Outstanding at December 31, 2017 1,817,758 $ 19.62 42 $ 11,846 Options exercisable (fully vested) at December 31, 2017 1,697,360 $ 19.64 39 $ 11,280
Schedule of Restricted Stock Activity	The following table summarizes restricted stock activity for the year ended December 31, 2017 : Shares Weighted Average Grant-Date Fair Value Unvested shares at January 1, 2017 1,607,288 $ 21.24 Granted 672,876 $ 21.85 Vested (818,962 ) $ 20.75 Forfeited (75,384 ) $ 21.60 Unvested shares at December 31, 2017 1,385,818 $ 21.80
Schedule of Performance Share Activity	The following table summarizes performance share activity for the year ended December 31, 2017 : Shares Weighted Average Grant-Date Fair Value Unvested shares at January 1, 2017 1,441,342 $ 23.72 Granted 243,571 $ 24.91 Canceled due to minimum performance goals not being met (286,179 ) $ 17.78 Forfeited (62,040 ) $ 24.95 Unvested shares at December 31, 2017 1,336,694 $ 25.15
Schedule of Range of Performance Shares that Can Be Earned	The following table summarizes the range of performance shares that can be earned as of December 31, 2017 : Performance Period Range Minimum Shares Target Shares Maximum Shares January 1, 2016 to December 31, 2018 0% to 200% — 253,882 507,764 January 1, 2017 to December 31, 2019 0% to 200% — 235,285 470,570 — 489,167 978,334

Impairment of Real Estate and58

Impairment of Real Estate and Impairment of Unconsolidated Entities (Tables)	12 Months Ended
	Dec. 31, 2017
Impairment of Real Estate and Impairment of Unconsolidated Entities [Abstract]
Impairment of Real Estate Included in Continuing Operations	The following table summarizes the Company’s impairment of real estate included in continuing operations: Years Ended December 31, 2017 2016 2015 (in thousands) 461 Dean Street (Apartment) Brooklyn, New York $ 44,288 $ — $ — Regional Malls: Shops at Northfield Stapleton Denver, Colorado — 68,821 — Boulevard Mall Amherst, New York — 52,510 — Shops at Wiregrass Tampa, Florida — 12,464 — Westchester's Ridge Hill Yonkers, New York — — 398,558 Office Buildings: Post Office Plaza Cleveland, Ohio — 11,800 — Illinois Science and Technology Park Skokie, Illinois — 7,900 26,246 Land inventory Las Vegas, Nevada — 1,230 16,307 Other — 2,100 10,323 $ 44,288 $ 156,825 $ 451,434
Schedule of Impairment of Unconsolidated Entities [Table Text Block]	The following table summarizes the Company’s impairment of unconsolidated entities: Years Ended December 31, 2017 2016 2015 (in thousands) Westchester’s Ridge Hill Yonkers, New York $ 10,600 $ — $ — Pacific Park Brooklyn Brooklyn, New York $ — $ 299,300 $ — Federally assisted housing apartment communities Various — — 10,295 Other — 7,100 3,549 $ 10,600 $ 306,400 $ 13,844
Unobservable Inputs Used to Determine the Fair Value of the Impairment of Real Estate	The following table presents quantitative information about the significant unobservable inputs used to determine the fair value of the impairment of real estate and unconsolidated investments for the years ended December 31, 2017, 2016 and 2015 : Quantitative Information about Level 3 Fair Value Measurements Fair Value Valuation Technique Unobservable Input Range of Input Values (in thousands) December 31, 2017 Impairment of real estate $ 152,575 Indicative bid Indicative bid N/A (1) Impairment of unconsolidated investments $ 225,890 Indicative bid Indicative bid N/A (1) December 31, 2016 Impairment of real estate $ 371,139 Indicative bids Indicative bids N/A (1) Impairment of real estate $ 18,500 Comparable property market analysis Price per square foot $39 per square foot Impairment of unconsolidated investments $ — Discounted cash flows Discount rate 9.8% Market capitalization rate 3.9% - 6.0% Impairment of unconsolidated investments $ 3,600 Indicative bids Indicative bids N/A (1) December 31, 2015 Impairment of real estate $ 615,797 Indicative bids Indicative bids N/A (1) Impairment of real estate $ 5,128 Comparable property market analysis Price per square foot $18 per square foot Impairment of unconsolidated investments $ 8,847 Indicative bids Indicative bids N/A (1) (1) These fair value measurements were derived from bona fide purchase offers from third party prospective buyers, subject to the Company’s corroboration for reasonableness.

Net Gain on Disposition of Fu59

Net Gain on Disposition of Full or Partial Interest in Rental Properties, Net of Tax (Tables)	12 Months Ended
	Dec. 31, 2017
Net Gain (Loss) on Disposition of Full or Partial Interest in Rental Properties, Net of Tax [Abstract]
Net Gain on Disposition of Full or Partial Interest in Rental Properties, Net of Tax	The following table summarizes the net gain (loss) on disposition of full or partial interest in rental properties, net of tax: Years Ended December 31, 2017 2016 2015 (in thousands) Retail Centers: Fairmont Cinema San Jose, California $ 4,128 $ — $ — QIC Transactions Various 2,197 21 — Avenue at Tower City Center & Tower City Parking Cleveland, Ohio 500 14,207 — Office Buildings: Illinois Science and Technology Park (4 buildings) Skokie, Illinois 3,771 — — Post Office Plaza Cleveland, Ohio (1,244 ) — — Terminal Tower Cleveland, Ohio — 14,391 — Aperture Center Albuquerque, New Mexico — (171 ) — Skylight Office Tower Cleveland, Ohio — — 1,746 Federally assisted housing apartments Various 2,693 — — Grand Lowry Lofts (Apartment Community) Denver, Colorado — 2,333 — Military Housing Various — 141,675 — Johns Hopkins Parking Garage Baltimore, Maryland — (623 ) — Other 6,947 664 — 18,992 172,497 1,746 Income tax effect (192 ) (51,213 ) (679 ) 18,800 121,284 1,067 Deed-in-lieu transaction: Boulevard Mall Amherst, New York 29,845 — — $ 48,645 $ 121,284 $ 1,067

Gain on Change in Control of 60

Gain on Change in Control of Interests (Tables)	12 Months Ended
	Dec. 31, 2017
Gain on Change in Control of Interests [Abstract]
Schedule of Gain on Change in Control of Interests	The following table summarizes the gain on change in control of interests: Years Ended December 31, 2017 2016 2015 (in thousands) University Park at MIT Cambridge, Massachusetts $ — $ — $ 463,643 Apartment Communities: Cherry Tree Strongsville, Ohio — — 7,391 Chestnut Lake Strongsville, Ohio — — 8,525 Stratford Crossing Wadsworth, Ohio — — 8,125 Other — — (1,405 ) $ — $ — $ 486,279
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The fair value of the acquisition was allocated as follows. All amounts are presented in thousands. Real Estate, net $ 1,121,786 Restricted cash 17,235 Notes and accounts receivable, net 1,801 Other assets (1) 103,804 1,244,626 Mortgage debt and notes payable, nonrecourse (363,147 ) Accounts payable, accrued expenses and other liabilities (2) (94,214 ) Net assets acquired $ 787,265 Gain on change in control of interests $ 463,643 Carrying value of previously held equity interests (62,534 ) Fair value of previously held equity interests (3) 401,109 Cash paid 386,156 Total $ 787,265 (1) Primarily consists of $78,000 of in-place leases and $20,000 of below-market ground leases with weighted-average lives at the time of acquisition of 3.6 years and 60 years , respectively. (2) Primarily consists of $49,000 of below-market tenant leases and $24,000 of above-market ground leases with weighted-average lives at the time of acquisition of 3.6 years and 58 years , respectively. (3) The significant assumptions used to value the previously held equity interests in the MIT Assets were determined to be Level 3 inputs. The weighted-average discount rate applied to cash flows and the weighted-average terminal capitalization rate were 7.0% and 6.0% , respectively.
Pro Forma Information of Business Acquisitions	The following unaudited supplemental pro forma operating data is presented for the year ended December 31, 2015, as if the step acquisition related to the MIT Assets was effective on January 1, 2014. The gain on change in control of interest related to this acquisition was adjusted to the assumed acquisition date. The unaudited supplemental pro forma operating data is not necessarily indicative of what the Company’s actual results of operations would have been assuming the transactions had been effective as set forth above, nor do they purport to represent the Company’s results of operations for future periods. The qualitative and quantitative effect to the pro forma operating data related to the remaining acquisitions described in the table above was not material. Pro Forma Adjustments As Reported Year Ended December 31, 2015 Remove: Gain on Change in Control of Interests (1) Pro Forma Adjustments (2) Pro Forma Year Ended December 31, 2015 (in thousands, except per share data) Revenues $ 978,231 $ — $ 43,742 $ 1,021,973 Earnings from continuing operations $ 544,810 $ (283,828 ) $ (15,211 ) $ 245,771 Net earnings attributable to common stockholders $ 496,042 $ (283,828 ) $ (15,211 ) $ 197,003 Weighted average shares outstanding - Basic 237,559,598 237,559,598 Net earnings attributable to common stockholders - Basic $ 2.05 $ 0.81 Weighted average shares outstanding - Diluted 250,848,286 250,848,286 Net earnings attributable to common stockholders - Diluted $ 1.97 $ 0.80 (1) Gain on change in control of interests related to MIT Assets of $463,643 , net of tax of $179,815 . (2) Represents additional depreciation and amortization expense related to the increased basis of real estate and intangible assets, plus pro forma earnings of the current ownership interests, less actual equity in earnings related to the Company’s prior ownership for the periods presented.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Reconciliation of REIT Earnings (Loss) Before Income Taxes to REIT Taxable Earnings [Table Text Block]	The following table reconciles REIT earnings (loss), before income taxes to the Company’s REIT taxable earnings: Year Ended December 31, 2017 December 31, 2016 (in thousands) Earnings (loss) before income taxes $ 144,890 $ (454,173 ) Net gain (loss) on disposition of full or partial interest in development projects (113 ) 136,687 Net gain on disposition of full or partial interest in rental properties 18,992 172,497 Gain on disposition of rental property in deed-in-lieu transaction 29,845 — Less: Noncontrolling interests (9,006 ) (6,078 ) Net earnings (loss) before income taxes 184,608 (151,067 ) Less: TRS earnings (loss) 9,399 (117,074 ) Less: SubREITs loss (390 ) (3,072 ) Less: Stand-alone TRSs & other earnings (loss) 1,281 (789 ) REIT earnings (loss) before income taxes $ 174,318 $ (30,132 ) Book to Tax Adjustments: Costs on land and rental properties under development expensed for tax purposes (4,991 ) (5,286 ) Impairment of real estate and land held for divestiture 10,600 160,595 Book gain on sales in excess of tax gain (14,588 ) (73,329 ) Excess of tax over financial statement depreciation and amortization 42,576 77,725 Revenues and expenses recognized in different periods for book and tax 11,170 (28,882 ) Other tax adjustments 4,188 4,540 Stock based compensation - compensation and depreciation limitations 19,376 20,122 Stock option exercises (18,114 ) (23,958 ) Conversion/exchange of senior debt — 26,895 Tax deductible restricted stock dividend (684 ) (592 ) REIT taxable earnings $ 223,851 $ 127,698
Schedule of Income Tax Expense (Benefit)	The following table summarizes the income tax expense (benefit) related to continuing operations before gains (loss) on disposal of real estate: Years Ended December 31, 2017 2016 2015 (in thousands) Current Federal $ 426 $ 335 $ 1,626 State 6,160 2,905 513 6,586 3,240 2,139 Deferred Federal (28,200 ) (310 ) (480,025 ) State — 803 (103,892 ) (28,200 ) 493 (583,917 ) Total income tax expense (benefit) $ (21,614 ) $ 3,733 $ (581,778 )
Reconciliation of Effective Tax Rate for Income Taxes from Continuing Operations	The effective tax rate for income taxes from continuing operations varies from the federal statutory rate of 35% due to the following items: Years Ended December 31, 2017 2016 2015 (dollars in thousands) Earnings (loss) before income taxes and earnings from unconsolidated entities $ 20,106 $ (190,640 ) $ (66,797 ) Equity in earnings of unconsolidated entities, net of impairment 124,784 (263,533 ) 28,762 Net gain (loss) on disposition of full or partial interest in development projects (113 ) 136,687 — Net gain on disposition of full or partial interest in rental properties 18,992 172,497 1,746 Gain on disposition of rental property in deed-in-lieu transaction 29,845 — — Less: Noncontrolling interests (9,006 ) (6,078 ) (13,258 ) Net earnings (loss) before income taxes 184,608 (151,067 ) (49,547 ) Less: REIT earnings (loss) 174,318 (30,132 ) — Less: SubREIT, Stand-alone TRS and other earnings (loss) 891 (3,861 ) — TRS income (loss) before income taxes 9,399 (117,074 ) (49,547 ) Income taxes computed at the statutory rate 3,290 (40,976 ) (17,341 ) Increase (decrease) in income tax resulting from: State taxes, net of federal benefit 1,137 (18,492 ) 2,207 State net operating loss, net of federal benefit 5,148 (7,586 ) 1,544 General business credits (243 ) 121 (307 ) Valuation allowance (1) (110,575 ) 127,726 (912 ) Charitable contributions (66 ) 151 1,127 Permanent adjustments (1,799 ) (1,520 ) 668 Conversion/Exchange of senior debt — — 20,501 Deferred tax adjustment due to REIT conversion — — (688,233 ) Valuation allowance adjustment due to REIT conversion — — 99,626 State tax rate change (2,128 ) — — Effects of federal tax law change (1) 70,676 — — Asset transfers into TRS 33,735 — — Other 125 (5,704 ) 21 Total income tax expense (benefit) $ (700 ) $ 53,720 $ (581,099 ) Effective tax rate (7.45 )% (45.89 )% 1,172.82 % The components of the deferred income tax expense (benefit) for continuing operations are as follows: Excess of tax over financial statement depreciation and amortization $ 1,612 $ 2,509 $ 2,097 Costs on land and rental properties under development expensed for tax purposes 7,121 211 13,520 Revenues and expenses recognized in different periods for tax and financial statement purposes (26,046 ) 112,205 174,072 Difference between tax and financial statements related to unconsolidated entities 33,143 (104,950 ) (24,474 ) Impairment of real estate and land held for divestiture (15,501 ) (1,165 ) (158,002 ) Deferred state taxes, net of federal benefit 5,350 (25,677 ) 2,893 Utilization of (addition to) tax loss carryforward excluding effect of stock options 34,387 (55,231 ) (8,566 ) Valuation allowance (110,575 ) 127,726 (912 ) General business credits 4 121 (307 ) Deferred tax adjustment due to REIT conversion — — (688,233 ) Valuation allowance adjustment due to REIT conversion — — 99,626 Deferred effect of state rate change (2,128 ) — — Effect of federal tax law change (2) 42,576 — — Alternative Minimum Tax credits 1,857 (1,857 ) — Deferred income tax expense (benefit) $ (28,200 ) $ 53,892 $ (588,286 ) (1) Includes the effect in the TRS of the 2017 federal tax rate change under the new tax law from 35% to 21% effective for years ending December 31, 2018 and beyond. (2) Includes the effect in the REIT and TRS of the 2017 federal tax rate change from 35% to 21% , and a $25,600 and $2,500 deferred tax benefit recorded for the REIT and the TRS, respectively, to record the AMT credit receivable as discussed below.
Deferred Tax Liability Components	The following table summarizes the components of the deferred income tax asset/(liability): Temporary Differences Deferred Tax December 31, 2017 December 31, 2016 December 31, 2017 December 31, 2016 (in thousands) Depreciation $ (9,843 ) $ (10,319 ) $ (2,869 ) $ (4,257 ) Capitalized costs 254,046 237,299 74,054 97,886 Tax loss carryforward 106,505 204,752 22,366 71,663 State loss carryforward, net of federal benefit — — 9,198 12,717 Valuation allowance — — (169,600 ) (280,175 ) Federal tax credits and other carryforwards — — 232 2,632 Basis in unconsolidated entities 265,071 301,850 77,268 124,513 Other (47,372 ) (67,564 ) (10,649 ) (24,979 ) Total $ 568,407 $ 666,018 $ — $ —
Schedule of Net Deferred Tax Liability	December 31, 2017 December 31, 2016 (in thousands) Deferred tax liabilities $ 116,829 $ 182,804 Deferred tax assets 286,429 462,979 Less: valuation allowance (169,600 ) (280,175 ) 116,829 182,804 Net deferred tax asset $ — $ —
Reconciliation of Unrecognized Tax Benefits	ties. A reconciliation of the total amounts of the Company’s unrecognized tax benefits, exclusive of interest and penalties, is summarized in the following table: Unrecognized Tax Benefit December 31, 2017 December 31, 2016 (in thousands) Beginning balance, January 1, $ 187 $ 478 Settlements — — Lapse of statutes of limitation — (291 ) Unrecognized tax benefits balance at December 31, $ 187 $ 187

Assets and Liabilities Held f62

Assets and Liabilities Held for Sale and Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2017
Discontinued Operations and Disposal Groups [Abstract]
Summary of Operating Results Included in Discontinued Operations	The following table summarizes the operating results related to discontinued operations: Years Ended December 31, 2016 2015 (in thousands) Revenues $ 14,792 $ 138,154 Expenses Operating expenses 12,540 97,021 Depreciation and amortization 23 34,554 12,563 131,575 Interest expense (3,540 ) (40,125 ) Amortization of mortgage procurement costs (61 ) (664 ) Loss before income taxes and loss from unconsolidated entities (1,372 ) (34,210 ) Loss from unconsolidated entities (1,400 ) (40,760 ) Loss before income taxes (2,772 ) (74,970 ) Income tax (benefit) (824 ) (22,498 ) Loss before gain on disposal group (1,948 ) (52,472 ) Gain on disposition of disposal group, net of tax 49,353 — Earnings (loss) from discontinued operations 47,405 (52,472 ) Noncontrolling interests Operating loss from disposal group and rental properties (776 ) (16,962 ) Earnings (loss) from discontinued operations attributable to Forest City Realty Trust, Inc. $ 48,181 $ (35,510 )
Summary of Gains (Losses) on Disposition of the Disposal Group	The following table summarizes the pre-tax gain (loss) on disposition of the Disposal Group: Years Ended December 31, 2016 2015 (in thousands) The Nets $ 136,247 $ — Barclays Center (56,481 ) — 79,766 — Income tax effect (1) (30,413 ) — $ 49,353 $ — (1) For the year ended December 31, 2016, primarily represents non-cash deferred taxes recognized upon the reversal of the deferred tax asset used to offset the taxable gain on the sales of assets held by the TRS.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Reconciliation of Basic and Diluted EPS Computations	The reconciliation of the basic and diluted EPS computations is shown in the following table: Years Ended December 31, 2017 2016 2015 Numerators (in thousands) Earnings (loss) from continuing operations attributable to Forest City Realty Trust, Inc. $ 206,030 $ (206,583 ) $ 531,552 Distributed and undistributed earnings allocated to participating securities (1,677 ) — (10,410 ) Earnings (loss) from continuing operations attributable to common stockholders - Basic $ 204,353 $ (206,583 ) $ 521,142 Undistributed earnings allocated to participating securities 506 — — Preferred distribution on Class A Common Units 709 — — Interest on convertible debt — — 6,606 Earnings (loss) from continuing operations attributable to common stockholders - Diluted $ 205,568 $ (206,583 ) $ 527,748 Net earnings (loss) attributable to Forest City Realty Trust, Inc. $ 206,030 $ (158,402 ) $ 496,042 Distributed and undistributed earnings allocated to participating securities (1,677 ) — (9,715 ) Net earnings (loss) attributable to common stockholders - Basic $ 204,353 $ (158,402 ) $ 486,327 Undistributed earnings allocated to participating securities 506 — — Preferred distribution on Class A Common Units 709 — — Interest on convertible debt — — 6,606 Net earnings (loss) attributable to common stockholders - Diluted $ 205,568 $ (158,402 ) $ 492,933 Denominators Weighted average shares outstanding - Basic 262,510,532 258,509,970 237,559,598 Effect of stock options and performance shares 763,611 — 1,342,524 Effect of convertible Class A Common Units 1,594,238 — — Effect of convertible debt — — 11,946,164 Weighted average shares outstanding - Diluted (1) 264,868,381 258,509,970 250,848,286 Earnings Per Share Earnings (loss) from continuing operations attributable to common stockholders - Basic $ 0.78 $ (0.80 ) $ 2.19 Earnings (loss) from continuing operations attributable to common stockholders - Diluted $ 0.78 $ (0.80 ) $ 2.10 Net earnings (loss) attributable to common stockholders - Basic $ 0.78 $ (0.61 ) $ 2.05 Net earnings (loss) attributable to common stockholders - Diluted $ 0.78 $ (0.61 ) $ 1.97 (1) Incremental shares from restricted stock and convertible securities aggregating 5,923,113 and 9,706,419 for the years ended December 31, 2017 and 2015, respectively, were not included in the computation of diluted EPS because their effect is anti-dilutive. Incremental shares from dilutive options, restricted stock, performance shares and convertible securities aggregating 9,528,889 for the year ended December 31, 2016 were not included in the computation of diluted EPS because their effect is anti-dilutive due to loss from continuing operations. Weighted-average options, restricted stock and performance shares of 1,333,046 , 2,706,145 and 2,392,982 for the years ended December 31, 2017, 2016 and 2015 , respectively, were not included in the computation of diluted EPS because their effect is anti-dilutive under the treasury stock method.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Financial Data of Reportable Operating Segments	The following tables summarize financial data for the Company’s reportable operating segments. All amounts are presented in thousands. December 31, 2017 December 31, 2016 Identifiable Assets Office $ 3,025,810 $ 3,192,840 Apartments 2,246,479 2,406,768 Retail 368,353 521,015 Total Operations 5,640,642 6,120,623 Development 2,020,273 1,799,138 Corporate 402,372 308,836 $ 8,063,287 $ 8,228,597 Years Ended December 31, Years Ended December 31, 2017 2016 2015 2017 2016 2015 Revenues Operating Expenses Office $ 449,636 $ 463,855 $ 425,052 $ 169,792 $ 185,983 $ 182,677 Apartments 286,358 291,615 267,633 126,317 137,313 142,926 Retail 53,335 79,660 138,955 37,710 52,127 90,489 Total Operations 789,329 835,130 831,640 333,819 375,423 416,092 Development 122,597 90,835 114,722 91,929 81,032 101,031 Corporate — — — 96,544 94,391 100,099 Other — 3,518 31,869 — 2,730 8,130 $ 911,926 $ 929,483 $ 978,231 $ 522,292 $ 553,576 $ 625,352 Depreciation and Amortization Capital Expenditures Office $ 125,825 $ 134,323 $ 109,176 $ 58,235 $ 40,066 $ 56,354 Apartments 77,956 77,556 78,593 29,569 19,383 27,722 Retail 9,343 20,662 51,326 4,608 9,885 9,999 Total Operations 213,124 232,541 239,095 92,412 69,334 94,075 Development 32,603 16,902 10,481 333,211 507,123 442,289 Corporate 2,626 1,279 2,582 10,218 99 205 Other — 126 767 — — — $ 248,353 $ 250,848 $ 252,925 $ 435,841 $ 576,556 $ 536,569
Reconciliation of Net Earning (Loss) to Adjusted EBIDTA by Segment	The reconciliations of net earnings (loss) to Adjusted EBITDA by segment are shown in the following tables. All amounts are presented in thousands. Year Ended December 31, 2017 Office Apartments Retail Total Operations Development Corporate Other Total Net earnings (loss) attributable to Forest City Realty Trust, Inc. $ 165,040 $ 179,036 $ 152,698 $ 496,774 $ (59,398 ) $ (231,346 ) $ — $ 206,030 Depreciation and amortization 129,202 89,885 65,052 284,139 26,620 2,626 — 313,385 Interest expense — — — — — 198,777 — 198,777 Amortization of mortgage procurement costs — — — — — 7,469 — 7,469 Income tax benefit — — — — — (21,422 ) — (21,422 ) Impairment of consolidated real estate — — — — 44,288 — — 44,288 Impairment of unconsolidated real estate — — 10,600 10,600 — — — 10,600 Loss on extinguishment of debt — — — — — 4,514 — 4,514 Net (gain) loss on disposition of full or partial interests in rental properties (2,589 ) (6,065 ) (37,467 ) (46,121 ) — — (46,121 ) Gain on disposition of unconsolidated entities (1,437 ) (71,037 ) (36,363 ) (108,837 ) — — — (108,837 ) Organizational transformation and termination benefits — — — — — 34,395 — 34,395 Adjusted EBITDA Attributable to Forest City Realty Trust, Inc. $ 290,216 $ 191,819 $ 154,520 $ 636,555 $ 11,510 $ (4,987 ) $ — $ 643,078 Year Ended December 31, 2016 Office Apartments Retail Total Operations Development Corporate Other Total Net earnings (loss) attributable to Forest City Realty Trust, Inc. $ 138,282 $ 102,249 $ (15,813 ) $ 224,718 $ (182,716 ) $ (422,592 ) $ 222,188 $ (158,402 ) Depreciation and Amortization 134,511 94,622 78,818 307,951 12,182 1,279 302 321,714 Interest Expense — — — — — 221,812 — 221,812 Amortization of mortgage procurement costs — — — — — 8,680 — 8,680 Income tax expense — — — — — 85,105 — 85,105 Interest rate swap breakage fee — — — — — 24,635 — 24,635 Impairment of consolidated real estate 19,700 2,100 133,795 155,595 1,230 — — 156,825 Impairment of unconsolidated real estate — — — — 306,400 — — 306,400 Loss on extinguishment of debt — — — — — 33,863 — 33,863 Net (gain) loss on disposition of full or partial interests in development project — — — — (136,687 ) — — (136,687 ) Net (gain) loss on disposition of full or partial interests in rental properties (13,782 ) (2,333 ) (15,216 ) (31,331 ) 324 — (141,675 ) (172,682 ) Gain on disposition of unconsolidated entities — — (12,613 ) (12,613 ) (553 ) — — (13,166 ) Organizational transformation and termination benefits — — — — — 31,708 — 31,708 Discontinued operations: Depreciation and Amortization - Real Estate — — — — — — 35 35 Loss on disposition of rental properties — — — — — — 56,481 56,481 Net gain on disposition of partial interest in other investment - Nets — — — — — — (136,247 ) (136,247 ) Nets pre-tax EBITDA — — — — — — 1,400 1,400 Adjusted EBITDA Attributable to Forest City Realty Trust, Inc. $ 278,711 $ 196,638 $ 168,971 $ 644,320 $ 180 $ (15,510 ) $ 2,484 $ 631,474 Year Ended December 31, 2015 Office Apartments Retail Total Operations Development Corporate Other Total Net earnings (loss) attributable to Forest City Realty Trust, Inc. $ 576,328 $ 82,944 $ (321,052 ) $ 338,220 $ (26,107 ) $ 198,327 $ (14,398 ) 496,042 Depreciation and Amortization 112,825 91,378 99,886 304,089 12,733 2,582 2,797 322,201 Interest Expense — — — — — 264,299 — 264,299 Amortization of mortgage procurement costs — — — — — 10,600 — 10,600 Income tax benefit — — — — — (603,597 ) — (603,597 ) Impairment of consolidated real estate 28,146 8,423 398,558 435,127 16,307 — — 451,434 Impairment of unconsolidated real estate — 12,460 — 12,460 1,384 — — 13,844 Loss on extinguishment of debt — — — — — 65,103 — 65,103 Net (gain) loss on disposition of full or partial interests in rental properties (1,746 ) — — (1,746 ) — — — (1,746 ) Gain on disposition of unconsolidated entities (1,009 ) (19,284 ) — (20,293 ) — — — (20,293 ) (Gain) loss on change in control of interests (463,643 ) (24,041 ) — (487,684 ) 1,405 — — (486,279 ) Organizational transformation and termination benefits — — — — — 48,125 — 48,125 Discontinued operations: Depreciation and Amortization — — — — — — 20,104 20,104 Nets pre-tax EBITDA — — — — — — 40,760 40,760 Adjusted EBITDA Attributable to Forest City Realty Trust, Inc. $ 250,901 $ 151,880 $ 177,392 $ 580,173 $ 5,722 $ (14,561 ) $ 49,263 $ 620,597

Summary of Significant Accoun65

Summary of Significant Accounting Policies (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Accounting Policies [Abstract]
Unrealized losses on foreign currency translation	$ 0	$ 0	$ 95,000
Unrealized losses on interest rate derivative contracts	8,612,000	14,473,000	67,888,000	[1]
Total unrealized losses	8,612,000	14,473,000	67,983,000
Noncontrolling Interest	(49,000)	(63,000)	(78,000)
Accumulated Other Comprehensive Loss	$ 8,563,000	$ 14,410,000	$ 67,905,000		$ 58,846,000
[1]	Includes unrealized losses on interest rate swaps accounted for as hedges held by certain of the Company’s equity method investees.

Summary of Significant Accoun66

Summary of Significant Accounting Policies (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Changes in Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	$ (14,410,000)	$ (67,905,000)	$ (58,846,000)
Gain (loss) recognized in accumulated OCI	476,000	(9,319,000)	(6,421,000)
Loss reclassified from accumulated OCI	5,371,000	62,814,000	29,013,000
One-time adjustment to deferred taxes on OCI related to REIT conversion	0	0	(31,651,000)
Total other comprehensive income (loss)	5,847,000	53,495,000	(9,059,000)
Ending Balance	(8,563,000)	(14,410,000)	(67,905,000)
Foreign Currency Translation [Member]
Schedule of Changes in Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	0	(95,000)	(84,000)
Gain (loss) recognized in accumulated OCI	0	95,000	24,000
Loss reclassified from accumulated OCI	0	0	0
One-time adjustment to deferred taxes on OCI related to REIT conversion			(35,000)
Total other comprehensive income (loss)	0	95,000	(11,000)
Ending Balance	0	0	(95,000)
Interest Rate Contracts [Member]
Schedule of Changes in Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(14,410,000)	(67,810,000)	(58,762,000)
Gain (loss) recognized in accumulated OCI	476,000	(9,414,000)	(6,445,000)
Loss reclassified from accumulated OCI	5,371,000	62,814,000	29,013,000
One-time adjustment to deferred taxes on OCI related to REIT conversion			(31,616,000)
Total other comprehensive income (loss)	5,847,000	53,400,000	(9,048,000)
Ending Balance	$ (8,563,000)	$ (14,410,000)	$ (67,810,000)

Summary of Significant Accoun67

Summary of Significant Accounting Policies (Details 2) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense	$ 120,431,000	$ 131,441,000	$ 157,166,000
Reclassification adjustment for rate swap breakage fee	0	24,635,000	0
Net gain on disposition of full or partial interest in rental properties, net of tax	(18,800,000)	(121,284,000)	(1,067,000)
Earnings from unconsolidated entities	(25,163,000)	(29,701,000)	(22,313,000)
Gain on change in control of interests	0	0	486,279,000
Total before income tax and noncontrolling interest	(144,890,000)	454,173,000	38,035,000
Income tax expense	(21,614,000)	3,733,000	(581,778,000)
Noncontrolling interest	9,006,000	6,078,000	13,258,000
Loss reclassified from accumulated OCI	(5,371,000)	(62,814,000)	(29,013,000)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense	2,817,000	34,889,000	37,852,000
Reclassification adjustment for rate swap breakage fee		24,635,000
Net gain on disposition of full or partial interest in rental properties, net of tax		113,000
Earnings from unconsolidated entities	2,568,000	3,192,000	3,722,000
Gain on change in control of interests			(900,000)
Total before income tax and noncontrolling interest	5,385,000	62,829,000	40,674,000
Income tax expense			(11,645,000)
Noncontrolling interest	(14,000)	(15,000)	(16,000)
Loss reclassified from accumulated OCI	$ 5,371,000	$ 62,814,000	$ 29,013,000

Summary of Significant Accoun68

Summary of Significant Accounting Policies (Details 3) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Termination benefits	$ 17,728,000	$ 13,032,000	$ 17,980,000
Strategic alternative costs	13,190,000	0	0
Shareholder activism costs	3,477,000	3,493,000	0
Reorganization costs	0	14,320,000	19,050,000
REIT conversion costs	0	863,000	11,095,000
Total	$ 34,395,000	$ 31,708,000	$ 48,125,000

Summary of Significant Accoun69

Summary of Significant Accounting Policies (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Accrued severance benefits, beginning balance	$ 9,969	$ 16,338	$ 4,982
Termination benefits expense	17,728	13,032	17,980
Payments	(13,723)	(19,401)	(6,624)
Accrued severance benefits, ending balance	$ 13,974	$ 9,969	$ 16,338

Summary of Significant Accoun70

Summary of Significant Accounting Policies (Details 5) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Non-cash changes to the balance sheet - Investing Activities
Projects under construction and development	$ (63,573,000)	$ (61,745,000)	$ 55,484,000
Completed rental properties	(239,367,000)	(1,257,606,000)	825,582,000
Restricted cash	8,670,000	(13,466,000)	8,969,000
Notes receivable	39,435,000	277,050,000	0
Investments in and advances to affiliates - due to dispositions or change in control	603,000	149,664,000	81,978,000
Investments in and advances to affiliates - other activity	(716,000)	3,228,000	20,852,000
Total non-cash effect on investing activities	(254,948,000)	(902,875,000)	992,865,000
Non-cash changes to the balance sheet - Financing Activities
Nonrecourse mortgage debt and notes payable, net	(194,116,000)	(935,479,000)	433,499,000
Convertible senior debt, net	(1,000)	(125,000)	(424,433,000)
Class A common stock	59,000	0	(76,823,000)
Additional paid-in capital	51,080,000	(14,755,000)	531,246,000
Treasury stock	0	0	(22,434,000)
Redeemable noncontrolling interest	0	(159,202,000)	0
Noncontrolling interest	(54,573,000)	19,087,000	(53,426,000)
Total non-cash effect on financing activities	$ (197,551,000)	$ (1,090,474,000)	$ 432,497,000

Summary of Significant Accoun71

Summary of Significant Accounting Policies (Details Textual)	3 Months Ended	12 Months Ended
	Dec. 31, 2015USD ($)$ / shares	Dec. 31, 2017USD ($)State$ / shares	Dec. 31, 2016USD ($)$ / shares	Dec. 31, 2015USD ($)$ / shares
Accounting Policies (Textual) [Abstract]
Assets | $		$ 8,063,287,000	$ 8,228,597,000
Number of states in which entity has consolidated assets | State		20
Occupancy rate of stabilized properties		92.00%
Stabilization, minimum years open and operating		1 year
Stabilization, maximum years open and operating		2 years
Common Stock, Par or Stated Value Per Share		$ 0.010
Excess tax benefits from share-based compensation as financing cash flows | $		$ 0	$ 0	$ 0
Maximum period from cessation of construction activity to project completion and availability for occupancy		1 year
Put/call provisions maximum contract term		7 years
Percentage of annual REIT taxable income to be distributed to as a dividend to shareholders		90.00%
Period after REIT conversion assets sold subject to income taxes		5 years
One-time adjustment to deferred taxes related to REIT conversion | $	$ 588,607,000
Apartments [Member]
Accounting Policies (Textual) [Abstract]
Lease terms		1 year
Arena [Member]
Accounting Policies (Textual) [Abstract]
Arena naming rights agreement term		20 years
Minimum [Member]
Accounting Policies (Textual) [Abstract]
Expected lease-up period		3 months
Term of compliance regulation on tax credit		0 years
Minimum [Member] | Office buildings, retail centers and parking facilities [Member]
Accounting Policies (Textual) [Abstract]
Lease terms		1 year
Minimum [Member] | Arena [Member]
Accounting Policies (Textual) [Abstract]
Arena founding partner and sponsor agreement term		1 year
Arena suite license agreement term		1 year
Minimum [Member] | Building and Building Improvements [Member]
Accounting Policies (Textual) [Abstract]
Estimated useful life of property		30 years
Maximum [Member]
Accounting Policies (Textual) [Abstract]
Expected lease-up period		12 months
Term of compliance regulation on tax credit		7 years
Maximum [Member] | Office buildings, retail centers and parking facilities [Member]
Accounting Policies (Textual) [Abstract]
Lease terms		30 years
Maximum [Member] | Arena [Member]
Accounting Policies (Textual) [Abstract]
Arena founding partner and sponsor agreement term		7 years
Arena suite license agreement term		7 years
Maximum [Member] | Building and Building Improvements [Member]
Accounting Policies (Textual) [Abstract]
Estimated useful life of property		50 years
Common Class A [Member]
Accounting Policies (Textual) [Abstract]
Common Stock, Par Value Per Share Prior to Adjustment	$ 0.333			$ 0.333
Common Stock, Par or Stated Value Per Share	0.01	$ 0.01	$ 0.01	0.01
Common Class B [Member]
Accounting Policies (Textual) [Abstract]
Common Stock, Par Value Per Share Prior to Adjustment	0.333			0.333
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0	$ 0.01	$ 0.01

Summary of Significant Accoun72

Summary of Significant Accounting Policies (Details Textual 1) $ in Millions	Dec. 31, 2017USD ($)entity
Variable Interest Entity [Line Items]
Maximum exposure to loss | $	$ 188
Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Number of variable interest entities	44
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Number of variable interest entities	38

Summary of Significant Accoun73

Summary of Significant Accounting Policies (Details Textual 2) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Ownership interest prior to exercise of promote option	25.00%
Ownership interest after exercise of promote option	29.63%
Increase to additional paid in capital	$ 10,931
Acquisitions of Partner's Interests		$ 38,951

Accounts Receivable, Net (Detai

Accounts Receivable, Net (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Components of accounts receivable, net
Accounts receivable	$ 228,419,000	$ 213,887,000
Allowance for doubtful accounts	(3,397,000)	(5,324,000)
Accounts Receivable, Net	225,022,000	208,563,000
Straight-line rent - tenants [Member]
Components of accounts receivable, net
Accounts receivable	110,201,000	119,366,000
Accounts receivables - tenants [Member]
Components of accounts receivable, net
Accounts receivable	11,206,000	13,263,000
AMT credit receivable [Member]
Components of accounts receivable, net
Accounts receivable	28,100,000	0
Other [Member]
Components of accounts receivable, net
Accounts receivable	$ 78,912,000	$ 81,258,000

Notes Receivable (Details)

Notes Receivable (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Notes receivable	$ 398,785,000	$ 383,163,000
Stapleton advances [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Notes receivable	$ 128,676,000	141,034,000
Weighted Average Interest Rate	8.53%
The Nets sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Notes receivable	$ 125,100,000	125,100,000
Weighted Average Interest Rate	4.50%
Barclays Center sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Notes receivable	$ 92,600,000	92,600,000
Weighted Average Interest Rate	4.50%
QIC [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Notes receivable	$ 36,935,000	0
Weighted Average Interest Rate	4.25%
Other[Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Notes receivable	$ 15,474,000	$ 24,429,000
Weighted Average Interest Rate	4.82%

Notes Receivable (Details Textu

Notes Receivable (Details Textuals) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Interest income on Stapleton Advances	$ 14,066,000	$ 12,781,000	$ 13,892,000
Notes receivable	$ 398,785,000	$ 383,163,000
Scenario, Forecast [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Notes receivable				$ 150,000,000

Investments in Unconsolidated77

Investments in Unconsolidated Entities (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Reconciliation of members' and partners' equity to the Company's Carrying Value
Total members’ and partners’ equity		$ 1,478,172	$ 1,428,242
Equity of other members and partners		1,021,051	998,199
Company’s net investment in unconsolidated entities		457,121	430,043
Basis differences	[1]	(25,838)	(16,356)
Advances to and on behalf of affiliates		(4,803)	500
Assets - Investments in and advances to unconsolidated entities		550,362	564,779
Liabilities - Cash Distributions and Losses in Excess of Investments in Unconsolidated Entities		(123,882)	(150,592)
Total Investments in Unconsolidated Entities, net		$ 426,480	$ 414,187
[1]	Represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the equity method venture level, which is typically amortized over the life of the related assets or liabilities. Basis differences relate to certain acquisition, transaction and other costs, as well as other-than-temporary impairments not reflected at the equity method venture level.

Investments in Unconsolidated78

Investments in Unconsolidated Entities (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Real Estate
Completed rental properties	$ 7,154,607,000	$ 7,112,347,000
Projects under construction and development	568,552,000	734,980,000
Land inventory	57,296,000	68,238,000
Total Real Estate	7,780,455,000	7,915,565,000
Less accumulated depreciation	(1,484,163,000)	(1,442,006,000)
Real Estate, net	6,296,292,000	6,473,559,000
Cash and equivalents	204,260,000	174,619,000
Other restricted cash	146,131,000	149,300,000
Other assets	242,435,000	274,614,000
Nonrecourse mortgage debt and notes payable, net	2,998,361,000	3,120,833,000
Members' and partners' equity	1,478,172,000	1,428,242,000
Operations:
Operating expenses	0	(2,730,000)	$ (8,130,000)
Depreciation and amortization	(248,353,000)	(250,848,000)	(252,925,000)
Interest and other income	53,651,000	46,229,000	37,739,000
Loss before income taxes	144,890,000	(454,173,000)	(38,035,000)
Discontinued operations:
Discontinued operations subtotal		(1,372,000)	(34,210,000)
Company's portion of gain on disposition of full or partial interest in rental properties	32,316,000	13,166,000	0
Net gain on disposition of full or partial interest in equity method investments	77,905,000	0	20,293,000
All equity method investees [Member]
Real Estate
Completed rental properties	6,577,155,000	6,303,559,000
Projects under construction and development	1,375,381,000	1,817,074,000
Land inventory	36,682,000	51,142,000
Total Real Estate	7,989,218,000	8,171,775,000
Less accumulated depreciation	(1,462,177,000)	(1,525,369,000)
Real Estate, net	6,527,041,000	6,646,406,000
Cash and equivalents	127,877,000	144,790,000
Other restricted cash	187,293,000	230,163,000
Other assets	482,308,000	541,145,000
Total Assets	7,324,519,000	7,562,504,000
Nonrecourse mortgage debt and notes payable, net	5,425,032,000	5,635,343,000
Other liabilities	421,315,000	498,919,000
Members' and partners' equity	1,478,172,000	1,428,242,000
Total Liabilities and Members' and Partners' Equity	7,324,519,000	7,562,504,000
Operations:
Revenues	958,696,000	809,209,000	1,100,094,000
Operating expenses	(494,114,000)	(343,036,000)	(491,804,000)
Depreciation and amortization	(198,706,000)	(225,712,000)	(244,126,000)
Interest and other income	17,637,000	16,297,000	19,721,000
Net gain (loss) on disposition of full or partial interest in rental properties	49,250,000	(24,475,000)	0
Interest expense including extinguishment of debt	(211,056,000)	(216,198,000)	(314,332,000)
Loss before income taxes	121,707,000	16,085,000	69,553,000
Discontinued operations:
Operating loss from rental properties	0	(7,561,000)	(64,766,000)
Discontinued operations subtotal	0	(7,561,000)	(64,766,000)
Net earnings (loss)	121,707,000	8,524,000	4,787,000
Company's portion of net earnings	25,163,000	29,701,000	22,313,000
Impairment of investments in unconsolidated entities	(10,600,000)	(306,400,000)	(13,844,000)
Company's portion of gain on disposition of full or partial interest in rental properties	32,316,000	13,166,000	0
Net gain on disposition of full or partial interest in equity method investments	77,905,000	0	20,293,000
Net earnings from unconsolidated entities	$ 124,784,000	$ (263,533,000)	$ 28,762,000

Investments in Unconsolidated79

Investments in Unconsolidated Entities (Details 2) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Net gain (loss) on full or partial interest in rental properties	$ 49,250,000	$ (24,475,000)	$ 0
Company's portion of gain on disposition of full or partial interest in rental properties	32,316,000	13,166,000	0
Net gain on disposition of full or partial interest in equity method investments	77,905,000	0	20,293,000
Federally assisted housing apartment communities [Member]
Schedule of Equity Method Investments [Line Items]
Net gain (loss) on full or partial interest in rental properties	27,942,000	0	0
Net gain on disposition of full or partial interest in equity method investments	49,800,000	0	0
Shops at Bruckner Boulevard [Member]
Schedule of Equity Method Investments [Line Items]
Net gain (loss) on full or partial interest in rental properties	21,308,000	0	0
Steinway Street Theaters [Member]
Schedule of Equity Method Investments [Line Items]
Net gain (loss) on full or partial interest in rental properties	0	29,489,000	0
Mesa del Sol (Land Inventory) [Member]
Schedule of Equity Method Investments [Line Items]
Net gain (loss) on full or partial interest in rental properties	0	(53,964,000)	0
Newport Landing [Member]
Schedule of Equity Method Investments [Line Items]
Net gain on disposition of full or partial interest in equity method investments	0	0	5,765,000
Eaton Ridge [Member]
Schedule of Equity Method Investments [Line Items]
Net gain on disposition of full or partial interest in equity method investments	0	0	4,745,000
Arbor Glen [Member]
Schedule of Equity Method Investments [Line Items]
Net gain on disposition of full or partial interest in equity method investments	0	0	3,422,000
Parkwood Village [Member]
Schedule of Equity Method Investments [Line Items]
Net gain on disposition of full or partial interest in equity method investments	0	0	2,817,000
Sutton Landing [Member]
Schedule of Equity Method Investments [Line Items]
Net gain on disposition of full or partial interest in equity method investments	0	0	2,535,000
South Bay Galleria [Member]
Schedule of Equity Method Investments [Line Items]
Net gain on disposition of full or partial interest in equity method investments	28,180,000	0	0
Suburban Cleveland office properties [Member]
Schedule of Equity Method Investments [Line Items]
Net gain on disposition of full or partial interest in equity method investments	1,437,000	0	0
Other [Member]
Schedule of Equity Method Investments [Line Items]
Net gain on disposition of full or partial interest in equity method investments	$ (1,512,000)	$ 0	$ 1,009,000

Investments in Unconsolidated80

Investments in Unconsolidated Entities (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)units	Dec. 31, 2015properties	Apr. 30, 2015properties
Apartment Communities transaction [Member]
Other Significant Noncash Transactions [Line Items]
Partner's equity ownership interest acquired		50.00%	50.00%
Number of properties acquired | properties		3	3
Company's equity ownership exchanged		50.00%	50.00%
Number of properties exchanged | properties		5	5
Federally assisted housing apartment communities [Member]
Other Significant Noncash Transactions [Line Items]
Number of apartment units sold | units	6,116
Net cash proceeds from sale	$ 59,080
South Bay Galleria [Member]
Other Significant Noncash Transactions [Line Items]
Net cash proceeds from sale	58,530
Shops at Bruckner Boulevard [Member]
Other Significant Noncash Transactions [Line Items]
Net cash proceeds from sale	$ 8,863

Other Assets (Details)

Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Components of other assets
Intangible assets, net	$ 106,786	$ 134,562
Prepaid expenses and other deferred costs, net	75,839	73,987
Lease procurement costs, net	59,810	66,065
Other assets	$ 242,435	$ 274,614

Other Assets (Details 1)

Other Assets (Details 1) $ in Thousands	Dec. 31, 2017USD ($)
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
2,018	$ 12,176
2,019	11,569
2,020	7,763
2,021	4,460
2,022	$ 3,483

Other Assets (Details Textual)

Other Assets (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Assets (Textual) [Abstract]
Amortization expense related to intangible assets	$ 21,925	$ 30,098	$ 28,019

Nonrecourse Mortgage Debt and84

Nonrecourse Mortgage Debt and Notes Payable, Net (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	$ 2,998,361,000	$ 3,120,833,000
Total weighted average rate	3.74%	3.62%
Operating Properties [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	$ 2,945,308,000	$ 2,981,756,000
Projects Under Construction and Development [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	53,053,000	139,077,000
Fixed Rate Debt [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	$ 1,655,757,000	$ 1,943,061,000
Total weighted average rate	4.27%	4.42%
Fixed Rate Debt [Member] | Operating Properties [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	$ 1,615,592,000	$ 1,874,206,000
Fixed Rate Debt [Member] | Projects Under Construction and Development [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	40,165,000	68,855,000
Variable Rate Debt, Taxable [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	$ 680,907,000	$ 578,671,000
Total weighted average rate	3.59%	2.96%
Variable Rate Debt, Taxable [Member] | Operating Properties [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	$ 680,907,000	$ 508,449,000
Variable Rate Debt, Taxable [Member] | Projects Under Construction and Development [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	0	70,222,000
Variable Rate Debt, Tax-Exempt [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	$ 661,697,000	$ 599,101,000
Total weighted average rate	2.58%	1.68%
Variable Rate Debt, Tax-Exempt [Member] | Operating Properties [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	$ 648,809,000	$ 599,101,000
Variable Rate Debt, Tax-Exempt [Member] | Projects Under Construction and Development [Member]
Mortgage Loans on Real Estate [Line Items]
Nonrecourse mortgage debt and notes payable, net	$ 12,888,000	$ 0

Nonrecourse Mortgage Debt and85

Nonrecourse Mortgage Debt and Notes Payable, Net (Details 1) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of nonrecourse mortgage debt and notes payable, net maturities
Nonrecourse mortgage debt and notes payable total maturities in 2018	$ 467,380
Nonrecourse mortgage debt and notes payable total maturities in 2019	480,819
Nonrecourse mortgage debt and notes payable total maturities in 2020	239,281
Nonrecourse mortgage debt and notes payable total maturities in 2021	195,128
Nonrecourse mortgage debt and notes payable total maturities in 2022	208,544
Nonrecourse mortgage debt and notes payable total maturities thereafter	1,438,666
Nonrecourse mortgage debt and notes payable, gross	3,029,818
Net unamortized mortgage procurement costs	31,457
Nonrecourse mortgage debt and notes payable, net	$ 2,998,361	$ 3,120,833

Revolving Credit Facility (Deta

Revolving Credit Facility (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Total available borrowings	$ 600,000,000	$ 600,000,000
Less outstanding balances:
Outstanding borrowings	0	0
Letters of credit	36,439,000	44,215,000
Available credit	$ 563,561,000	$ 555,785,000

Revolving Credit Facility (De87

Revolving Credit Facility (Details Textual)	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Line of Credit Facility [Line Items]
Total available borrowings	$ 600,000,000	$ 600,000,000
Line of Credit Maximum Borrowings Under Accordion Provision	750,000,000
Unamortized debt procurement costs	1,798,000	$ 2,757,000
Old maximum borrowing capacity [Member]
Line of Credit Facility [Line Items]
Total available borrowings	500,000,000
New maximum borrowing capacity [Member]
Line of Credit Facility [Line Items]
Total available borrowings	$ 600,000,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Number of Credit Facility extension options	2
Term of Credit Facility Extension Options	6 months
Annual facility fee percentage of total available borrowings	0.25%
Available borrowing that could be used for letter of credits (and/or surety bonds 2014 and prior)	$ 150,000,000
LIBOR [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Variable rate basis spread of debt instrument	1.56%
Prime Rate [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Variable rate basis spread of debt instrument	4.50%
Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Annual facility fee percentage of total available borrowings	0.20%
Minimum [Member] | LIBOR [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Variable rate basis spread of debt instrument	1.15%
Minimum [Member] | Prime Rate [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Variable rate basis spread of debt instrument	0.15%
Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Annual facility fee percentage of total available borrowings	0.35%
Maximum [Member] | LIBOR [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Variable rate basis spread of debt instrument	1.85%
Maximum [Member] | Prime Rate [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Variable rate basis spread of debt instrument	0.85%
Current Period [Member] | LIBOR [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Variable rate basis spread of debt instrument	1.25%
Current Period [Member] | Prime Rate [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Variable rate basis spread of debt instrument	0.25%

Term Loan Facility, Net (Detail

Term Loan Facility, Net (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Term Loan Facility, Net [Abstract]
Total outstanding borrowings	$ 335,000,000	$ 335,000,000
Net unamortized debt procurement costs	(1,332,000)	(1,732,000)
Total	$ 333,668,000	$ 333,268,000

Term Loan Facility, Net (Deta89

Term Loan Facility, Net (Details Textual)	12 Months Ended
	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Term loan, maximum borrowing capacity	$ 335,000,000
Term Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Variable rate basis spread of debt instrument	1.36%
Term Loan [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Variable rate basis spread of debt instrument	1.30%
Term Loan [Member] | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Variable rate basis spread of debt instrument	2.20%
Term Loan [Member] | Prime Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Variable rate basis spread of debt instrument	0.30%
Term Loan [Member] | Prime Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Variable rate basis spread of debt instrument	1.20%
Current Period [Member] | Term Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Variable rate basis spread of debt instrument	1.45%
Current Period [Member] | Term Loan [Member] | Prime Rate [Member]
Debt Instrument [Line Items]
Variable rate basis spread of debt instrument	0.45%

Convertible Senior Debt (Detail

Convertible Senior Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Jul. 31, 2013	Jul. 31, 2011
Schedule of convertible senior debt
Convertible senior debt, net	$ 113,236	$ 113,237
Net unamortized debt procurement costs	(599)	(1,056)
Convertible senior debt, net	112,637	112,181
Notes due 2018 [Member]
Schedule of convertible senior debt
Convertible senior debt, net	73,215	73,216
Notes due 2020 [Member]
Schedule of convertible senior debt
Convertible senior debt, net	$ 40,021	$ 40,021
Convertible Senior Notes [Member] | Notes due 2018 [Member]
Schedule of convertible senior debt
Interest rate	4.25%	4.25%		4.25%
Convertible Senior Notes [Member] | Notes due 2020 [Member]
Schedule of convertible senior debt
Interest rate	3.63%	3.63%	3.625%

Convertible Senior Debt (Deta91

Convertible Senior Debt (Details 1) - USD ($)	Mar. 17, 2016	Mar. 14, 2016	Jan. 20, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Conversion [Line Items]
Loss on Extinguishment of Debt				$ (2,961,000)	$ (32,960,000)	$ (65,086,000)
Notes due 2016 [Member]
Debt Conversion [Line Items]
Aggregate Principal			$ 125,000
Cash payments to noteholders			0
Loss on Extinguishment of Debt			$ 59,000
Notes due 2018 [Member]
Debt Conversion [Line Items]
Aggregate Principal	$ 4,000,000	$ 77,310,000
Cash payments to noteholders	4,707,000	90,958,000
Loss on Extinguishment of Debt	$ 795,000	15,370,000
Notes due 2020 [Member]
Debt Conversion [Line Items]
Aggregate Principal		76,334,000
Cash payments to noteholders		86,858,000
Loss on Extinguishment of Debt		$ 12,823,000
2016, 2018 and 2020 Senior Notes [Member]
Debt Conversion [Line Items]
Aggregate Principal				157,769,000
Cash payments to noteholders				182,523,000
Loss on Extinguishment of Debt				$ 29,047,000
Common Class A [Member] | Notes due 2016 [Member]
Debt Conversion [Line Items]
Class A Common Shares Issued			9,298
Common Class A [Member] | Notes due 2018 [Member]
Debt Conversion [Line Items]
Class A Common Shares Issued	0	0
Common Class A [Member] | Notes due 2020 [Member]
Debt Conversion [Line Items]
Class A Common Shares Issued		0
Common Class A [Member] | 2016, 2018 and 2020 Senior Notes [Member]
Debt Conversion [Line Items]
Class A Common Shares Issued				9,298

Convertible Senior Debt (Deta92

Convertible Senior Debt (Details 2) - Notes due 2018 [Member]	3 Months Ended
	Dec. 31, 2017$ / shares	Jun. 30, 2017	Jun. 30, 2016	Dec. 20, 2017$ / shares	Jun. 09, 2017$ / shares	Jun. 10, 2015$ / shares
Debt Conversion [Line Items]
Debt Instrument, Convertible, Conversion Ratio	47.8122	47.2567	46.6375
Conversion price per share	$ 21.67			$ 20.92	$ 21.16	$ 21.44

Convertible Senior Debt (Deta93

Convertible Senior Debt (Details 3) - Notes due 2020 [Member]	3 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2015	Dec. 31, 2017$ / shares	Dec. 20, 2017$ / shares	Jun. 09, 2017$ / shares	Jun. 10, 2015$ / shares
Debt Conversion [Line Items]
Debt Instrument, Convertible, Conversion Ratio	42.3105	41.7561	42.8079
Conversion price per share			$ 24.21	$ 23.36	$ 23.63	$ 23.95

Convertible Senior Debt (Deta94

Convertible Senior Debt (Details 4) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest incurred, capitalized and paid
Interest incurred	$ 141,582,000	$ 170,080,000	$ 194,041,000
Interest capitalized	(21,151,000)	(38,639,000)	(36,875,000)
Net interest expense from continuing operations	120,431,000	131,441,000	157,166,000
Interest incurred from discontinued operations	0	3,540,000	40,125,000
Cash paid for interest (net of amount capitalized)	$ 116,987,000	$ 130,766,000	$ 200,781,000

Convertible Senior Debt (Deta95

Convertible Senior Debt (Details Textuals)	3 Months Ended				12 Months Ended
	Dec. 31, 2017USD ($)$ / shares	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2017USD ($)$ / shares	Dec. 20, 2017$ / shares	Jun. 09, 2017$ / shares	Dec. 31, 2016	Jun. 10, 2015$ / shares	Jul. 31, 2013USD ($)	Jul. 31, 2011USD ($)
Notes due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Conversion Ratio	47.8122	47.2567	46.6375
Principal amount of senior notes	$ 1,000				$ 1,000
Conversion price per share | $ / shares	$ 21.67				$ 21.67	$ 20.92	$ 21.16		$ 21.44
Notes due 2018 [Member] | Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Convertible senior notes issued											$ 350,000,000
Interest rate	4.25%				4.25%			4.25%			4.25%
Notes due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Conversion Ratio		42.3105		41.7561	42.8079
Principal amount of senior notes	$ 1,000				$ 1,000
Conversion price per share | $ / shares	$ 24.21				$ 24.21	$ 23.36	$ 23.63		$ 23.95
Notes due 2020 [Member] | Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Convertible senior notes issued										$ 300,000,000
Interest rate	3.63%				3.63%			3.63%		3.625%
Initial conversion ratio [Member] | Notes due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Conversion Ratio					46.1425
Initial conversion ratio [Member] | Notes due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Conversion Ratio					41.3129

Derivative Instruments and He96

Derivative Instruments and Hedging Activities (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Other Assets [Member] | Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Asset Derivative, Current Notional	$ 432,393,000	$ 300,218,000
Asset Derivative, Fair Value	4,991,000	5,601,000
Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Asset Derivative, Current Notional	169,984,000	170,318,000
Asset Derivative, Fair Value	4,107,000	4,117,000
Accounts Payable, Accrued Expenses and Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Liability Derivative, Current Notional	270,093,000	350,681,000
Liability Derivative, Fair Value	1,515,000	13,946,000
Accounts Payable, Accrued Expenses and Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Liability Derivative, Current Notional	36,280,000	37,044,000
Liability Derivative, Fair Value	11,330,000	12,256,000
Interest rate caps [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Asset Derivative, Current Notional	69,518,000	69,518,000
Asset Derivative, Fair Value	0	0
Interest rate caps [Member] | Accounts Payable, Accrued Expenses and Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Liability Derivative, Current Notional	0	0
Liability Derivative, Fair Value	0	0
Interest rate swaps [Member] | Other Assets [Member] | Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Asset Derivative, Current Notional	63,372,000	64,248,000
Asset Derivative, Fair Value	1,129,000	593,000
Interest rate swaps [Member] | Accounts Payable, Accrued Expenses and Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Liability Derivative, Current Notional	34,078,000	34,666,000
Liability Derivative, Fair Value	863,000	1,504,000
TROR [Member] | Other Assets [Member] | Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Asset Derivative, Current Notional	369,021,000	235,970,000
Asset Derivative, Fair Value	3,862,000	5,008,000
TROR [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Asset Derivative, Current Notional	100,466,000	100,800,000
Asset Derivative, Fair Value	4,107,000	4,117,000
TROR [Member] | Accounts Payable, Accrued Expenses and Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Liability Derivative, Current Notional	236,015,000	316,015,000
Liability Derivative, Fair Value	652,000	12,442,000
TROR [Member] | Accounts Payable, Accrued Expenses and Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Fair Value of Derivative Instruments
Liability Derivative, Current Notional	36,280,000	37,044,000
Liability Derivative, Fair Value	$ 11,330,000	$ 12,256,000

Derivative Instruments and He97

Derivative Instruments and Hedging Activities (Details 1) - Cash Flow Hedging [Member] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative instruments gain loss in financial statements
Gain (loss) recognized in OCI (effective portion)	$ 476,000	$ (9,414,000)	$ (12,478,000)
Gain (loss) reclassified from accumulated OCI, effective amount	(5,369,000)	(62,948,000)	(40,652,000)
Gain (loss) reclassified from accumulated OCI, ineffective amount	(16,000)	119,000	(22,000)
Interest rate caps and interest rate swaps [Member]
Derivative instruments gain loss in financial statements
Gain (loss) recognized in OCI (effective portion)	476,000	(9,414,000)	(12,478,000)
Interest rate caps and interest rate swaps [Member] | Interest expense [Member]
Derivative instruments gain loss in financial statements
Gain (loss) reclassified from accumulated OCI, effective amount	(2,801,000)	(35,008,000)	(37,831,000)
Gain (loss) reclassified from accumulated OCI, ineffective amount	(16,000)	119,000	(21,000)
Interest rate caps and interest rate swaps [Member] | Earnings (loss) from Unconsolidated Entities, Gross of Tax [Member]
Derivative instruments gain loss in financial statements
Gain (loss) reclassified from accumulated OCI, effective amount	(2,568,000)	(3,192,000)	(3,721,000)
Gain (loss) reclassified from accumulated OCI, ineffective amount	$ 0	0	(1,000)
Interest rate caps and interest rate swaps [Member] | Interest rate swap breakage fee [Member]
Derivative instruments gain loss in financial statements
Gain (loss) reclassified from accumulated OCI, effective amount		(24,635,000)
Gain (loss) reclassified from accumulated OCI, ineffective amount		0
Interest rate caps and interest rate swaps [Member] | Net gain (loss) on disposition of full or partial interest in rental properties, net of tax [Member]
Derivative instruments gain loss in financial statements
Gain (loss) reclassified from accumulated OCI, effective amount		(113,000)
Gain (loss) reclassified from accumulated OCI, ineffective amount		$ 0
Interest rate caps and interest rate swaps [Member] | Net Gain on Change in Control of Interests [Member]
Derivative instruments gain loss in financial statements
Gain (loss) reclassified from accumulated OCI, effective amount			900,000
Gain (loss) reclassified from accumulated OCI, ineffective amount			$ 0

Derivative Instruments and He98

Derivative Instruments and Hedging Activities (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Not Designated as Hedging Instrument [Member]
Impact of gains and losses related to derivative instruments
Net gain (loss) recognized on derivatives	$ 871	$ (271)	$ 5,109
TROR [Member] | Not Designated as Hedging Instrument [Member]
Impact of gains and losses related to derivative instruments
Net gain (loss) recognized on derivatives	916	(164)	5,266
Interest rate caps and interest rate swaps [Member] | Not Designated as Hedging Instrument [Member]
Impact of gains and losses related to derivative instruments
Net gain (loss) recognized on derivatives	(45)	(107)	(157)
Fair Value Hedging [Member] | TROR [Member] | Designated as Hedging Instrument [Member]
Impact of gains and losses related to derivative instruments
Net gain (loss) recognized on derivatives	$ 10,644	$ (4,624)	$ 2,794	[1]
[1]	The net gain (loss) recognized in interest expense from the change in fair value of the underlying TROR borrowings was $(10,644), $4,624 and $(2,794) for the years ended December 31, 2017, 2016 and 2015, respectively, offsetting the gain (loss) recognized on the TROR.

Derivative Instruments and He99

Derivative Instruments and Hedging Activities (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
SIFMA Rate	1.71%
Minimum [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Derivative, term of contract	1 year
Minimum [Member] | Interest rate caps [Member]
Derivative [Line Items]
Derivative, term of contract	1 year
Maximum [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Derivative, term of contract	10 years
Maximum [Member] | Interest rate caps [Member]
Derivative [Line Items]
Derivative, term of contract	3 years
Not Designated as Hedging Instrument [Member] | TROR [Member]
Derivative [Line Items]
Notional amount	$ 136,746
Cash Flow Hedging [Member]
Derivative [Line Items]
Interest rate swap breakage fee		$ 24,635
Loss on cash flow hedges to be reclassified within next twelve months	3,674
Fair Value Hedging [Member] | TROR [Member]
Derivative [Line Items]
Notional amount	605,036
Fair Value Hedging [Member] | Designated as Hedging Instrument [Member] | TROR [Member]
Derivative [Line Items]
Net gain (loss) from change in fair value of underlying TROR borrowings recognized in interest expense	$ (10,644)	$ 4,624	$ (2,794)

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Fair value measurement, recurring basis [Member] - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowing subject to TROR	$ (3,210,000)	$ 7,434,000
Total fair value	(6,957,000)	(9,050,000)
Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	1,129,000	593,000
Derivative liabilities	(863,000)	(1,504,000)
TROR [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	7,969,000	9,125,000
Derivative liabilities	(11,982,000)	(24,698,000)
Level 1 [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowing subject to TROR	0	0
Total fair value	0	0
Level 1 [Member] | Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	0	0
Derivative liabilities	0	0
Level 1 [Member] | TROR [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	0	0
Derivative liabilities	0	0
Level 2 [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowing subject to TROR	0	0
Total fair value	266,000	(911,000)
Level 2 [Member] | Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	1,129,000	593,000
Derivative liabilities	(863,000)	(1,504,000)
Level 2 [Member] | TROR [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	0	0
Derivative liabilities	0	0
Level 3 [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Fair value adjustment to the borrowing subject to TROR	(3,210,000)	7,434,000
Total fair value	(7,223,000)	(8,139,000)
Level 3 [Member] | Interest rate swaps [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	0	0
Derivative liabilities	0	0
Level 3 [Member] | TROR [Member]
Financial assets and liabilities and redeemable noncontrolling interests on a recurring basis
Derivative assets	7,969,000	9,125,000
Derivative liabilities	$ (11,982,000)	$ (24,698,000)

Fair Value Measurements (Det101

Fair Value Measurements (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (8,139)	$ (7,975)
Total realized and unrealized gains (losses):
Included in earnings	916	(164)
Ending balance	(7,223)	(8,139)
Net TROR [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(15,573)	(10,785)
Total realized and unrealized gains (losses):
Included in earnings	11,560	(4,788)
Ending balance	(4,013)	(15,573)
Fair value adjustment to the borrowings subject to TROR [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	7,434	2,810
Total realized and unrealized gains (losses):
Included in earnings	(10,644)	4,624
Ending balance	$ (3,210)	$ 7,434

Fair Value Measurements (Det102

Fair Value Measurements (Details 2) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value	$ (7,223)	$ (8,139)	$ (7,975)
Fair value adjustment to the borrowings subject to TROR [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value	(3,210)	$ 7,434	$ 2,810
Bond Valuation [Member] | TROR [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value	(4,013)
Bond Valuation [Member] | Fair value adjustment to the borrowings subject to TROR [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value	$ (3,210)
Fair Value, Measurements, Recurring [Member] | Bond Valuation [Member] | Minimum [Member] | TROR [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Bond valuation	$ 98.81
Fair Value, Measurements, Recurring [Member] | Bond Valuation [Member] | Minimum [Member] | Fair value adjustment to the borrowings subject to TROR [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Bond valuation	98.81
Fair Value, Measurements, Recurring [Member] | Bond Valuation [Member] | Maximum [Member] | TROR [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Bond valuation	118
Fair Value, Measurements, Recurring [Member] | Bond Valuation [Member] | Maximum [Member] | Fair value adjustment to the borrowings subject to TROR [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Bond valuation	$ 101.87

Fair Value Measurements (Det103

Fair Value Measurements (Details 3) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value of nonrecourse mortgage debt and notes payable (exclusive of the fair value of derivatives), bank revolving credit facility and senior and subordinated debt
Carrying value	$ 3,444,666	$ 3,566,282
Fair value	3,460,227	3,561,909
Nonrecourse mortgage debt and notes payable, net [Member]
Fair Value of nonrecourse mortgage debt and notes payable (exclusive of the fair value of derivatives), bank revolving credit facility and senior and subordinated debt
Carrying value	2,998,361	3,120,833
Fair value	2,995,559	3,105,587
Term loan facility, net [Member]
Fair Value of nonrecourse mortgage debt and notes payable (exclusive of the fair value of derivatives), bank revolving credit facility and senior and subordinated debt
Carrying value	333,668	333,268
Fair value	333,726	333,527
Convertible senior debt, net [Member]
Fair Value of nonrecourse mortgage debt and notes payable (exclusive of the fair value of derivatives), bank revolving credit facility and senior and subordinated debt
Carrying value	112,637	112,181
Fair value	$ 130,942	$ 122,795

Fair Value Measurements (Det104

Fair Value Measurements (Details Textual) $ in Thousands	Dec. 31, 2017USD ($)
Total Return Swap [Member] | Fair Value Hedging [Member]
Notional amount of TROR borrowings subject to fair value adjustments [Line Items]
Notional amount of TROR borrowings subject to fair value adjustment	$ 605,036

Commitments and Contingencie105

Commitments and Contingencies (Details) - Completion Guarantee [Member] $ in Thousands	Dec. 31, 2017USD ($)
Guarantor Obligations [Line Items]
Total Costs	$ 2,645,700
Percentage Completed	82.00%
Openings [Member]
Guarantor Obligations [Line Items]
Total Costs	$ 2,029,900
Percentage Completed	93.00%
Under construction [Member]
Guarantor Obligations [Line Items]
Total Costs	$ 615,800
Percentage Completed	48.00%

Commitments and Contingencie106

Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies [Line Items]
Outstanding letters of credit	$ 36,439	$ 44,215
Tax Indemnity Guarantee [Member]
Commitments and Contingencies [Line Items]
Maximum exposure/payment	120,655
Guarantee of Indebtedness of Others [Member]
Commitments and Contingencies [Line Items]
Maximum exposure/payment	1,493,000
Completion Guarantee [Member]
Commitments and Contingencies [Line Items]
Maximum exposure/payment	2,645,700
Land development project [Member] | Completion Guarantee [Member]
Commitments and Contingencies [Line Items]
Maximum exposure/payment	$ 563

Capital Stock (Detail Textuals)

Capital Stock (Detail Textuals) - USD ($)	1 Months Ended	9 Months Ended	12 Months Ended
	May 31, 2015	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 12, 2017
Class of Stock [Line Items]
Common stock conversion ratio pursuant to the Reclassification Agreement			1.31
Class B common shares reclassified						18,788,163
Class A common shares issued pursuant to the Reclassification Agreement						24,612,495
Common stock voting rights, votes per share		one vote per share
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs		$ 9,305,000	$ 9,305,000	$ 3,896,000
Common Stock, Par or Stated Value Per Share			$ 0.010
Proceeds from issuance of Class A common stock, net of transaction costs			$ 0	$ 0	$ 806,500,000
Preferred Stock, Par Value Per Share			$ 0.01	$ 0.01
Preferred Stock, No Par Value, Prior to Adjustment				0
Common Class A [Member]
Class of Stock [Line Items]
Common Stock, Par Value Per Share Prior to Adjustment					$ 0.333
Common Stock, Par or Stated Value Per Share			0.01	0.01	$ 0.01
Issuance of Class A shares in equity offering, shares	37,375,000				37,375,000
Shares Issued, Price Per Share	$ 22.50
Proceeds from issuance of Class A common stock, net of transaction costs	$ 806,500,000
Common Class B [Member]
Class of Stock [Line Items]
Common Stock, Par Value Per Share Prior to Adjustment					$ 0.333
Common Stock, Par or Stated Value Per Share			$ 0	$ 0.01	$ 0.01

Dividends (Details)

Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 29, 2017	Nov. 29, 2017	Sep. 18, 2017	Aug. 22, 2017	Jun. 23, 2017	May 17, 2017	Mar. 27, 2017	Mar. 01, 2017	Dec. 23, 2016	Nov. 30, 2016	Sep. 16, 2016	Aug. 18, 2016	Jun. 24, 2016	May 17, 2016	Mar. 18, 2016	Feb. 18, 2016	Dec. 31, 2017	Dec. 31, 2016
Dividends Payable [Line Items]
Amount per share																	$ 0.46	$ 0.34
Total cash payments																	$ 121,610	$ 88,452
Quarterly
Dividends Payable [Line Items]
Amount per share		$ 0.14		$ 0.14		$ 0.09		$ 0.09		$ 0.06		$ 0.06		$ 0.06		$ 0.06
Total cash payments	$ 37,344		$ 37,343		$ 23,482		$ 23,441		$ 15,620		$ 15,621		$ 15,623		$ 15,596
E&P
Dividends Payable [Line Items]
Amount per share																$ 0.10
Total cash payments															$ 25,992

Dividends (Details 1)

Dividends (Details 1) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Dividends Payable [Line Items]
Amount per share	$ 0.46	$ 0.34
Percentage of dividends declared	100.00%	100.00%
Ordinary income [Member]
Dividends Payable [Line Items]
Amount per share	$ 0.04	$ 0.11
Percentage of dividends declared	9.44%	31.49%
Capital gain [Member]
Dividends Payable [Line Items]
Amount per share	$ 0.42	$ 0.23
Percentage of dividends declared	90.56%	68.51%

Class A Common Units and Rel110

Class A Common Units and Related Party Transactions (Detail Textual)	1 Months Ended						3 Months Ended	12 Months Ended
	Sep. 30, 2017USD ($)	Aug. 31, 2017USD ($)$ / sharesshares	Mar. 31, 2017USD ($)shares	Jan. 31, 2017USD ($)	Sep. 30, 2015USD ($)shares	May 31, 2008USD ($)project	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)	Jan. 31, 2016USD ($)	Aug. 31, 2006property
Amount paid for acquisition of BCR Entities interests								$ 0	$ 39,395,000	$ 312,000
Units outstanding | shares								1,111,044	1,940,788
Carrying value of Class A Common Units								$ 56,674,000	$ 99,000,000
Ownership Interest Prior to Exchange		100.00%
Basis for determining the number of Units to be exchanged for rental property | $ / shares		$ 20
Reduction to noncontrolling interest								416,283,000	501,161,000
Reduction to completed rental properties								7,154,607,000	7,112,347,000
Nonrecourse mortgage debt and notes payable, net								2,998,361,000	3,120,833,000
Additional Paid in Capital								2,537,538,000	2,483,275,000
Payment for the overpayment of closing costs	$ 222,000
Increase to Class A common stock								2,653,000	2,587,000
Common Class A [Member]
Increase to Class A common stock								2,653,000	$ 2,399,000
BCR transaction [Member]
Number of retail, office and residential operating properties | property												30
Amount paid for acquisition of BCR Entities interests										$ 10
Percentage of ownership after acquisition of noncontrolling interests										100.00%
Percentage of ownership sold									51.00%
Number of projects | project						2
Amount to be paid over 15 year period						$ 121,000,000
Payment period of cost of interest transferred						15 years
Initial cash received by BCR Entities						$ 49,249,000
Initial discounted amount						$ 56,495,000
Obligation included in accounts payable, accrued expenses and other liabilities								3,855,000	$ 3,672,000
Final payment due April 2023 under purchase method of accounting								5,000,000
Distribution preference payment								$ 709,000	660,000
Related party transaction amount									11,000,000
BCR exchange transaction [Member]
Exchange of Class A common units for rental property, units exchanged | shares		686,865
Reduction to noncontrolling interest		$ 35,037,000	$ 7,288,000		$ 52,663,000
Reduction to completed rental properties		45,044,000
Nonrecourse mortgage debt and notes payable, net		34,382,000
Additional Paid in Capital		$ 22,805,000	$ 7,287,000		$ 52,319,000
Exchange of Class A Common Units for Class A shares, units exchanged | shares			142,879		1,032,402
BCR exchange transaction [Member] | Common Class A [Member]
Exchange of Class A Common Units for Class A shares, shares issued | shares			142,879		1,032,402
Increase to Class A common stock			$ 1,000		$ 344,000
BCR share of retainage release [Member]
Related party transaction amount							$ 997,000
RMS reimbursement under Reimbursement Agreement [Member]
Related party transaction amount							4,060,000		1,207,000
Ratners purchase of life insurance policy [Member]
Related party transaction amount							$ 826,000
Shops at Bruckner Boulevard [Member] | BCR transaction [Member]
Tax indemnity payment				$ 482,000
625 Fulton [Member] | BCR transaction [Member]
Tax indemnity payment				1,558,000					$ 4,680,000
Tax Indemnity Guarantee [Member] | BCR transaction [Member]
Accounts payable, related parties				$ 482,000							$ 6,238,000
Development fee [Member] | BCR transaction [Member]
Accounts payable, related parties										$ 11,000,000

Leases (Details)

Leases (Details) $ in Thousands	Dec. 31, 2017USD ($)
Minimum future rental income to be received on non-cancelable operating leases
2,018	$ 343,765
2,019	320,345
2,020	298,282
2,021	267,313
2,022	247,632
Thereafter	1,129,277
Total rental income	$ 2,606,614

Leases (Details 1)

Leases (Details 1) $ in Thousands	Dec. 31, 2017USD ($)
Minimum fixed rental payments under long-term leases
2,018	$ 9,523
2,019	10,899
2,020	11,060
2,021	11,180
2,022	10,769
Thereafter	312,661
Total rental payment	$ 366,092

Leases (Details 2)

Leases (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases [Abstract]
Rent expense	$ 16,659	$ 16,886	$ 14,032

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation costs	$ 26,884	$ 25,463	$ 31,835
Less amount capitalized into qualifying real estate projects	(8,146)	(5,661)	(7,717)
Amount charged to operating expenses	18,738	19,802	24,118
Depreciation expense on capitalized stock-based compensation	880	607	894
Total stock-based compensation expense	19,618	20,409	25,012
Deferred income tax benefit	511	610	9,629
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation costs	590	937	1,314
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation costs	17,133	14,788	17,211
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation costs	$ 9,161	$ 9,738	$ 13,310

Stock-Based Compensation (De115

Stock-Based Compensation (Details 1) - Stock Options [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.12%	1.41%	1.71%
Expected volatility	25.10%	26.60%	30.80%
Expected dividend yield	1.69%	1.04%	0.00%
Expected term (in years)	5 years 6 months	5 years 6 months	5 years 6 months

Stock-Based Compensation (De116

Stock-Based Compensation (Details 2) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding at January 1, 2017 | shares	2,545,031
Shares granted | shares	26,112
Shares exercised | shares	(90,545)
Shares forfeited/expired | shares	(662,840)
Shares outstanding at December 31, 2017 | shares	1,817,758
Options, exercisable (fully vested) at December 31, 2017 | shares	1,697,360
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price, Outstanding at January 1, 2017 | $ / shares	$ 31.25
Weighted Average Exercise Price, Granted | $ / shares	21.83
Weighted Average Exercise Price, Exercised | $ / shares	16.54
Weighted Average Exercise Price, Forfeited/expired | $ / shares	64.77
Weighted Average Exercise Price, Outstanding at December 31, 2017 | $ / shares	19.62
Weighted Average Exercise Price, exercisable (fully vested) at December 31, 2017 | $ / shares	$ 19.64
Weighted Average Remaining Contractual Term, Outstanding at December 31, 2017	42 months
Weighted Average Remaining Contractual Term, Exercisable (fully vested) at December 31, 2017	39 months
Intrinsic Value, Outstanding at December 31, 2017 | $	$ 11,846
Intrinsic Value, Exercisable (fully vested) at December 31, 2017 | $	$ 11,280

Stock-Based Compensation (De117

Stock-Based Compensation (Details 3) - Restricted Stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Shares, Nonvested, Number of Shares [Roll Forward]
Unvested shares at January 1, 2017	1,607,288
Shares granted	672,876
Shares vested	(818,962)
Shares forfeited	(75,384)
Unvested shares at December 31, 2017	1,385,818	1,607,288
Restricted Shares, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted Average Grant-Date Fair Value, Unvested shares at January 1, 2017	$ 21.24
Weighted Average Grant-Date Fair Value, Granted	21.85	$ 20.94	$ 24.62
Weighted Average Grant-Date Fair Value, Vested	20.75
Weighted Average Grant-Date Fair Value, Forfeited	21.60
Weighted Average Grant-Date Fair Value, Unvested shares at December 31, 2017	$ 21.80	$ 21.24

Stock-based Compensation (De118

Stock-based Compensation (Details 4) - Performance Shares [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Performance Shares, Nonvested, Number of Shares [Roll Forward]
Unvested shares at January 1, 2017	1,441,342
Shares granted	243,571
Shares canceled due to minimum performance goals not being met	(286,179)
Shares forfeited	(62,040)
Unvested shares at December 31, 2017	1,336,694	1,441,342
Performance Shares, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted Average Grant-Date Fair Value, Unvested shares at January 1, 2017	$ 23.72
Weighted Average Grant-Date Fair Value, Granted	24.91	$ 17.27	$ 32.14
Weighted Average Grant-Date Fair Value, Canceled	17.78
Weighted Average Grant-Date Fair Value, Forfeited	24.95
Weighted Average Grant-Date Fair Value, Unvested shares at December 31, 2017	$ 25.15	$ 23.72

Stock-Based Compensation Stock-

Stock-Based Compensation Stock-Based Compensation (Details 5) - Performance Shares [Member]	12 Months Ended
	Dec. 31, 2017shares
Minimum shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares that can be earned	0
Target shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares that can be earned	489,167
Maximum shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares that can be earned	978,334
0% to 200% [Member] | Minimum shares [Member] | January 1, 2016 to December 31, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares that can be earned	0
0% to 200% [Member] | Minimum shares [Member] | January 1, 2017 to December 31, 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares that can be earned	0
0% to 200% [Member] | Target shares [Member] | January 1, 2016 to December 31, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares that can be earned	253,882
0% to 200% [Member] | Target shares [Member] | January 1, 2017 to December 31, 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares that can be earned	235,285
0% to 200% [Member] | Maximum shares [Member] | January 1, 2016 to December 31, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares that can be earned	507,764
0% to 200% [Member] | Maximum shares [Member] | January 1, 2017 to December 31, 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares that can be earned	470,570
Minimum [Member] | 0% to 200% [Member] | January 1, 2016 to December 31, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage range of performance shares that can be earned	0.00%
Minimum [Member] | 0% to 200% [Member] | January 1, 2017 to December 31, 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage range of performance shares that can be earned	0.00%
Maximum [Member] | 0% to 200% [Member] | January 1, 2016 to December 31, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage range of performance shares that can be earned	200.00%
Maximum [Member] | 0% to 200% [Member] | January 1, 2017 to December 31, 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage range of performance shares that can be earned	200.00%

Stock-Based Compensation (De120

Stock-Based Compensation (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares to be issued under the Plan		21,750,000
Number of shares available for granting		5,499,394
Maximum annual award to a nonemployee director, aggregate grant-date fair value		$ 250,000
Amount of grant date fair value expensed for awards granted to retirement-eligible grantees		$ 867,000	$ 1,166,000	$ 1,926,000
Weighted average grant-date fair value of stock options		$ 21.83
Cash received from stock options exercised		$ 1,498,000	$ 1,158,000	$ 1,488,000
Class A common shares repurchased, shares		272,121	390,703
Purchase of treasury stock, shares				222,537
Class A common shares repurchased		$ 6,082,000	$ 7,945,000
Purchase of treasury stock				$ 5,543,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum annual award to individuals, shares		500,000
Maximum term of stock options		10 years
Weighted average grant-date fair value of stock options		$ 4.79	$ 5	$ 7.79
Total intrinsic value of stock options exercised		$ 664,000	$ 661,000	$ 841,000
Cash received from stock options exercised		1,498,000	1,158,000	1,488,000
Income tax benefit realized		0	$ 0	$ 0
Unrecognized compensation cost		$ 84,000
Weighted average period of unrecognized compensation cost		3 months
Restricted Shares and Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum annual award to individuals, shares		500,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost		$ 12,431,000
Weighted average period of unrecognized compensation cost		21 months
Weighted average grant-date fair value		$ 21.85	$ 20.94	$ 24.62
Total fair value of shares that vested		$ 16,993,000	$ 17,663,000	$ 13,883,000
Shares forfeited		818,962
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost		$ 4,779,000
Weighted average period of unrecognized compensation cost		21 months
Weighted average grant-date fair value		$ 24.91	$ 17.27	$ 32.14
Minimum performance period		1 year
Shares canceled due to minimum performance goals not being met		(286,179)
Minimum [Member] | Employee [Member] | Stock Options and Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards		3 years
Minimum [Member] | Nonemployee director [Member] | Stock Options and Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards		1 year
Maximum [Member] | Employee [Member] | Stock Options and Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards		4 years
Maximum [Member] | Nonemployee director [Member] | Stock Options and Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards		3 years
Subsequent Event [Member] | Scenario, Forecast [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares canceled due to minimum performance goals not being met	776,509
Shares forfeited	71,018

Write-Off of Abandoned Devel121

Write-Off of Abandoned Development Projects and Demolition Costs (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Write-off of Abandoned Development Projects and Demolition Costs [Abstract]
Write-offs of abandoned development projects and demolition costs	$ 1,596	$ 10,348	$ 9,534
Write-offs of abandoned development projects and demolition costs of unconsolidated entities	$ 2,107	$ 327	$ 10,191

Impairment of Real Estate an122

Impairment of Real Estate and Impairment of Unconsolidated Entities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	$ 44,288,000	$ 156,825,000	$ 451,434,000
461 Dean Street [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	44,288,000	0	0
Shops at Northfield Stapleton [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	0	68,821,000	0
Boulevard Mall [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	0	52,510,000	0
Shops at Wiregrass [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	0	12,464,000	0
Westchester's Ridge Hill [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	0	0	398,558,000
Post Office Plaza [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	0	11,800,000	0
Illinois Science and Technology Park [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	0	7,900,000	26,246,000
Land Inventory [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	0	1,230,000	16,307,000
Other [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	$ 0	$ 2,100,000	$ 10,323,000

Impairment of Real Estate an123

Impairment of Real Estate and Impairment of Unconsolidated Entities (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Impairment of Unconsolidated Entities [Line Items]
Impairment of unconsolidated entities	$ 10,600,000	$ 306,400,000	$ 13,844,000
Westchester's Ridge Hill [Member]
Schedule of Impairment of Unconsolidated Entities [Line Items]
Impairment of unconsolidated entities	10,600,000	0	0
Pacific Park Brooklyn [Member]
Schedule of Impairment of Unconsolidated Entities [Line Items]
Impairment of unconsolidated entities	0	299,300,000	0
Federally assisted housing apartment communities [Member]
Schedule of Impairment of Unconsolidated Entities [Line Items]
Impairment of unconsolidated entities	0	0	10,295,000
Other [Member]
Schedule of Impairment of Unconsolidated Entities [Line Items]
Impairment of unconsolidated entities	$ 0	$ 7,100,000	$ 3,549,000

Impairment of Real Estate an124

Impairment of Real Estate and Impairment of Unconsolidated Entities (Details 2) - Fair Value, Measurements, Nonrecurring [Member]	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2017USD ($)
Impairment of real estate [Member] | Indicative bids [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	$ 371,139,000	$ 615,797,000	$ 152,575,000
Impairment of real estate [Member] | Comparable property market analysis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	$ 18,500,000	$ 5,128,000
Price per square foot	39	18
Impairment of unconsolidated investment [Member] | Indicative bids [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	$ 3,600,000	$ 8,847,000	$ 225,890,000
Impairment of unconsolidated investment [Member] | Discounted cash flows [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	$ 0
Discount rate	9.80%
Impairment of unconsolidated investment [Member] | Minimum [Member] | Discounted cash flows [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Market capitalization rate	3.90%
Impairment of unconsolidated investment [Member] | Maximum [Member] | Discounted cash flows [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Market capitalization rate	6.00%

Impairment of Real Estate an125

Impairment of Real Estate and Impairment of Unconsolidated Entities (Detail Textuals) ft² in Millions	12 Months Ended
	Dec. 31, 2017USD ($)aft²properties	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)aproperties	Oct. 31, 2016	Jan. 31, 2016	Jun. 30, 2014USD ($)
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Impairment of unconsolidated entities | $	$ 10,600,000	$ 306,400,000	$ 13,844,000
Shops at Wiregrass [Member]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Percentage of ownership sold				49.00%
Land Inventory [Member]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Area of project/parcel | a			13.5
Area of Land Parcel Sold | a			6.1
Westchester's Ridge Hill [Member]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Percentage of ownership sold	49.00%				51.00%
Impairment of unconsolidated entities | $	$ 10,600,000	0	$ 0
Pacific Park Brooklyn [Member]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Percentage of ownership sold						70.00%
Area of project/parcel | a	22
Net cash proceeds from partial sale | $						$ 208,275,000
Buildings Commenced in 2015			2
Impairment of unconsolidated entities | $	$ 0	299,300,000	$ 0
Federally assisted housing apartment communities [Member]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Impairment of unconsolidated entities | $	$ 0	$ 0	$ 10,295,000
Number of Real Estate Properties	47
Federally assisted housing apartment communities, unconsolidated investments [Member]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Number of Real Estate Properties	44
Federally assisted housing apartment communities, consolidated investments [Member]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Number of Real Estate Properties	3
Phase I [Member] | Pacific Park Brooklyn [Member]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Number of Buildings	7
Area of Real Estate Property | ft²	3.1
Phase II [Member] | Pacific Park Brooklyn [Member]
Impairment of Real Estate and Impairment of Unconsolidated Entities [Line Items]
Number of Buildings	7
Area of Real Estate Property | ft²	3.3

Net Gain (Loss) on Dispositi126

Net Gain (Loss) on Disposition of Full or Partial Interest in Development Projects, Net of Tax (Details Textuals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Net Gain (Loss) on Disposition of Full or Partial Interest in Development Projects, Net of Tax [Abstract]
Disposition of Interest in Development Project Net Cash Proceeds		$ 151,776
Pre-tax net gain on disposition of full or partial interest in development projects	$ (113)	$ 136,687

Net Gain on Disposition of F127

Net Gain on Disposition of Full or Partial Interest in Rental Properties, Net of Tax (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	$ 18,992,000	$ 172,497,000	$ 1,746,000
Income tax effect	(192,000)	(51,213,000)	(679,000)
Net gain on disposition of full or partial interest in rental properties, net of tax	18,800,000	121,284,000	1,067,000
Gain on disposition of rental property in deed-in-lieu transaction	29,845,000	0	0
Total gain on disposition of full or partial interest in rental properties, net of tax and deed-in-lieu transaction	48,645,000	121,284,000	1,067,000
Fairmont Cinema [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	4,128,000	0	0
QIC Transactions [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	2,197,000	21,000	0
Avenue at Tower City Center & Tower City Parking [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	500,000	14,207,000	0
Illinois Science and Technology Park [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	3,771,000	0	0
Post Office Plaza [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	(1,244,000)	0	0
Terminal Tower [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	0	14,391,000	0
Aperture Center [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	0	(171,000)	0
Skylight Office Tower [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	0	0	1,746,000
Federally assisted housing apartment communities [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	2,693,000	0	0
Grand Lowry Lofts [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	0	2,333,000	0
Military Housing [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	0	141,675,000	0
Johns Hopkins Parking Garage [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	0	(623,000)	0
Other [Member]
Significant Acquisitions and Disposals [Line Items]
Net gain on disposition of full or partial interest in rental properties	6,947,000	664,000	0
Boulevard Mall [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on disposition of rental property in deed-in-lieu transaction	$ 29,845,000	$ 0	$ 0

Net Gain on Disposition of F128

Net Gain on Disposition of Full or Partial Interest in Rental Properties (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disposal Group, not including discontinued operations [Line Items]
Net gain on disposition of full or partial interest in rental properties	$ 18,992,000	$ 172,497,000	$ 1,746,000
Notes receivable	398,785,000	383,163,000
Military Housing [Member]
Disposal Group, not including discontinued operations [Line Items]
Net cash proceeds from sale		208,305,000
Intangible assets acquired by the buyer		29,000,000
Investments in unconsolidated entities, net acquired by the buyer		14,600,000
Net gain on disposition of full or partial interest in rental properties	0	141,675,000	0
Terminal Tower [Member]
Disposal Group, not including discontinued operations [Line Items]
Net cash proceeds from sale		38,027,000
Sale Leaseback Transaction, Deferred Gain, Net		7,917,000
Net gain on disposition of full or partial interest in rental properties	0	14,391,000	$ 0
Shops at Northfield Stapleton [Member]
Disposal Group, not including discontinued operations [Line Items]
Net cash proceeds from sale	50,019,000
Notes receivable	$ 36,935,000
Note receivable, interest rate	4.25%
Westchester's Ridge Hill [Member]
Disposal Group, not including discontinued operations [Line Items]
Net cash proceeds from sale		$ 75,448,000
Percentage of ownership sold		51.00%
Debt assumed by the outside partner		$ 169,369,000
Ballston Quarter [Member]
Disposal Group, not including discontinued operations [Line Items]
Percentage of ownership sold		49.00%
Debt assumed by the outside partner		$ 20,825,000
Partner cash investment into joint venture		36,269,000
Shops at Wiregrass [Member]
Disposal Group, not including discontinued operations [Line Items]
Net cash proceeds from sale		$ 24,906,000
Percentage of ownership sold		49.00%
Debt assumed by the outside partner		$ 40,497,000

Gain on Change in Control of129

Gain on Change in Control of Interests (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gain on Change in Control of Interests [Line Items]
Gain on change in control of interests	$ 0	$ 0	$ 486,279,000
University Park at MIT [Member]
Gain on Change in Control of Interests [Line Items]
Gain on change in control of interests	0	0	463,643,000
Cherry Tree [Member]
Gain on Change in Control of Interests [Line Items]
Gain on change in control of interests	0	0	7,391,000
Chestnut Lake [Member]
Gain on Change in Control of Interests [Line Items]
Gain on change in control of interests	0	0	8,525,000
Stratford Crossing [Member]
Gain on Change in Control of Interests [Line Items]
Gain on change in control of interests	0	0	8,125,000
Other [Member]
Gain on Change in Control of Interests [Line Items]
Gain on change in control of interests	$ 0	$ 0	$ (1,405,000)

Gain on Change in Control of130

Gain on Change in Control of Interests (Details 1) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2015
Gain on Change in Control of Interest [Line Items]
Gain on change in control of interests		$ 0	$ 0	$ 486,279,000
University Park at MIT [Member]
Gain on Change in Control of Interest [Line Items]
Real Estate, net					$ 1,121,786,000
Restricted cash					17,235,000
Notes and accounts receivable, net					1,801,000
Other assets					103,804,000
Total Assets					1,244,626,000
Mortgage debt and notes payable, nonrecourse					(363,147,000)
Accounts payable, accrued expenses and other liabilities					(94,214,000)
Net assets acquired					$ 787,265,000
Gain on change in control of interests				463,643,000
Carrying value of previously held equity interests				(62,534,000)
Fair value of previously held equity interests	[1]			401,109,000
Cash paid				386,156,000
Total				$ 787,265,000
[1]	(3)The significant assumptions used to value the previously held equity interests in the MIT Assets were determined to be Level 3 inputs. The weighted-average discount rate applied to cash flows and the weighted-average terminal capitalization rate were 7.0% and 6.0%, respectively.

Gain on Change in Control of131

Gain on Change in Control of Interests (Details 2) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues		$ 911,926,000	$ 929,483,000	$ 978,231,000
Pro forma revenues				1,021,973,000
Earnings from continuing operations		$ 215,036,000	$ (200,505,000)	544,810,000
Pro Forma earnings from continuing operations				245,771,000
Net earnings attributable to common shareholders				496,042,000
Pro forma net earnings attributable to common shareholders				$ 197,003,000
Weighted average shares outstanding, Basic		262,510,532	258,509,970	237,559,598
Net earnings attributable to common shareholders - Basic		$ 0.78	$ (0.61)	$ 2.05
Weighted average shares outstanding - Diluted	[1]	264,868,381	258,509,970	250,848,286
Net earnings attributable to common shareholders - Diluted		$ 0.78	$ (0.61)	$ 1.97
Proforma weighted average shares outstanding - Basic				237,559,598
Pro Forma net earnings attributable to common shareholders - Basic				$ 0.81
Pro Forma weighted average shares outstanding - Diluted				250,848,286
Pro Forma net earnings attributable to common shareholders- Diluted				$ 0.80
Gain on change in control of interests [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Pro forma adjustment to revenues				$ 0
Pro forma adjustment to earnings (loss) from continuing operations				(283,828,000)
Pro forma adjustment to net earnings (loss) attributable to common shareholders				(283,828,000)
Other Pro Forma Adjustments [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Pro forma adjustment to revenues				43,742,000
Pro forma adjustment to earnings (loss) from continuing operations				(15,211,000)
Pro forma adjustment to net earnings (loss) attributable to common shareholders				$ (15,211,000)
[1]	(1)Incremental shares from restricted stock and convertible securities aggregating 5,923,113 and 9,706,419 for the years ended December 31, 2017 and 2015, respectively, were not included in the computation of diluted EPS because their effect is anti-dilutive. Incremental shares from dilutive options, restricted stock, performance shares and convertible securities aggregating 9,528,889 for the year ended December 31, 2016 were not included in the computation of diluted EPS because their effect is anti-dilutive due to loss from continuing operations. Weighted-average options, restricted stock and performance shares of 1,333,046, 2,706,145 and 2,392,982 for the years ended December 31, 2017, 2016 and 2015, respectively, were not included in the computation of diluted EPS because their effect is anti-dilutive under the treasury stock method.

Gain on Change in Control of132

Gain on Change in Control of Interests (Details Textuals)	1 Months Ended	12 Months Ended
	Jun. 30, 2015USD ($)properties	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)properties	Apr. 30, 2015properties
Gain on Change in Control of Interests [Line Items]
Gain on change in control of interests		$ 0	$ 0	$ 486,279,000
University Park at MIT [Member]
Gain on Change in Control of Interests [Line Items]
Gain on change in control of interests		$ 0	$ 0	463,643,000
Gain on change in control of interests, tax				$ 179,815,000
Apartment Communities transaction [Member]
Gain on Change in Control of Interests [Line Items]
Partner's equity ownership interest acquired				50.00%	50.00%
Number of properties acquired | properties				3	3
Company's equity ownership exchanged				50.00%	50.00%
Number of properties exchanged | properties				5	5
Ownership percentage subsequent to acquisition					100.00%
University Park at MIT [Member]
Gain on Change in Control of Interests [Line Items]
Partner's equity ownership interest acquired	49.00%
Number of properties acquired | properties	7
Ownership percentage subsequent to acquisition	100.00%
Number of parking facilities | properties	2
Ownership Percentage prior to acquisition	51.00%
Weighted average discount rate	7.00%
Weighted average capitalization rate	6.00%
Gain on change in control of interests				$ 463,643,000
Leases, Acquired-in-Place [Member] | University Park at MIT [Member]
Gain on Change in Control of Interests [Line Items]
Acquired Leases	$ 78,000,000
Acquired leases, Weighted Average Useful Life	3 years 7 months
Below-market tenant leases [Member] | University Park at MIT [Member]
Gain on Change in Control of Interests [Line Items]
Acquired leases, Weighted Average Useful Life	3 years 7 months
Below Market Lease, Net	$ 49,000,000
Below-market ground leases [Member] | University Park at MIT [Member]
Gain on Change in Control of Interests [Line Items]
Ground Leases, Net	$ 20,000,000
Acquired Ground Leases, Weighted Average Useful Life	60 years
Above-market ground leases [Member] | University Park at MIT [Member]
Gain on Change in Control of Interests [Line Items]
Ground Leases, Net	$ 24,000,000
Acquired Ground Leases, Weighted Average Useful Life	58 years
May 2015 Common Stock Issuance [Member] | University Park at MIT [Member]
Gain on Change in Control of Interests [Line Items]
Net proceeds to finance acquisition	$ 386,156,000

Gain (Loss) on Extinguishmen133

Gain (Loss) on Extinguishment of Debt (Details Textuals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gain (Loss) on Extinguishment of Debt [Abstract]
Loss on extinguishment of debt	$ (2,961)	$ (32,960)	$ (65,086)

Income Taxes (Details)

Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of REIT Earnings (Loss) Before Income Taxes to REIT Taxable Earnings [Line Items]
Earnings (loss) before income taxes	$ 144,890,000	$ (454,173,000)	$ (38,035,000)
Net (gain) loss on disposition of full or partial interest in development projects, net of tax	(113,000)	136,687,000
Net gain on disposition of full or partial interest in rental properties	18,992,000	172,497,000	1,746,000
Gain on disposition of rental property in deed-in-lieu transaction	29,845,000	0	0
Less: Noncontrolling interests	(9,006,000)	(6,078,000)	(13,258,000)
Net earnings (loss) before income taxes	184,608,000	(151,067,000)	(49,547,000)
REIT income loss before income taxes	174,318,000	(30,132,000)	$ 0
Costs on land and rental properties under development expensed for tax purposes	(4,991,000)	(5,286,000)
Impairment of real estate and land held for divestiture	10,600,000	160,595,000
Book gain on sales (in excess of) less than tax gain	(14,588,000)	(73,329,000)
Excess of tax over financial statement depreciation and amortization	42,576,000	77,725,000
Revenue and expenses recognized in different periods for tax and financial statement purposes	11,170,000	(28,882,000)
Other Tax Adjustments	4,188,000	4,540,000
Stock based compensation - compensation and depreciation limitations	19,376,000	20,122,000
Stock option exercises	(18,114,000)	(23,958,000)
Conversion/exchange of senior debt	0	26,895,000
Tax deductible restricted stock dividend	(684,000)	(592,000)
REIT taxable earnings	223,851,000	127,698,000
TRS [Member]
Reconciliation of REIT Earnings (Loss) Before Income Taxes to REIT Taxable Earnings [Line Items]
Less: Non-REIT subsidiaries	9,399,000	(117,074,000)
SubREITs [Member]
Reconciliation of REIT Earnings (Loss) Before Income Taxes to REIT Taxable Earnings [Line Items]
Less: Non-REIT subsidiaries	(390,000)	(3,072,000)
Stand-alone TRSs & other [Member]
Reconciliation of REIT Earnings (Loss) Before Income Taxes to REIT Taxable Earnings [Line Items]
Less: Non-REIT subsidiaries	$ 1,281,000	$ (789,000)

Income Taxes (Details 1)

Income Taxes (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
Federal	$ 426,000	$ 335,000	$ 1,626,000
State	6,160,000	2,905,000	513,000
Current income tax expense (benefit)	6,586,000	3,240,000	2,139,000
Deferred
Federal	(28,200,000)	(310,000)	(480,025,000)
State	0	803,000	(103,892,000)
Deferred income tax expense (benefit)	(28,200,000)	493,000	(583,917,000)
Total income tax expense (benefit)	$ (21,614,000)	$ 3,733,000	$ (581,778,000)

Income Taxes (Details 2)

Income Taxes (Details 2) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective tax rate for income taxes from continuing operations
Earnings (loss) before income taxes and earnings from unconsolidated entities	$ (20,106,000)	$ 190,640,000	$ 66,797,000
Equity in earnings of unconsolidated entities, net of impairment	124,784,000	(263,533,000)	28,762,000
Net gain (loss) on disposition of full or partial interest in development projects	(113,000)	136,687,000	0
Net gain on disposition of full or partial interest in rental properties	18,992,000	172,497,000	1,746,000
Gain on disposition of rental property in deed-in-lieu transaction	29,845,000	0	0
Less: Noncontrolling interests	(9,006,000)	(6,078,000)	(13,258,000)
Loss from continuing operations, including noncontrolling interest, before income taxes	184,608,000	(151,067,000)	(49,547,000)
Less: REIT loss	174,318,000	(30,132,000)	0
TRS income (loss) before income taxes	9,399,000	(117,074,000)	(49,547,000)
Income taxes computed at the statutory rate	3,290,000	(40,976,000)	(17,341,000)
Increase (decrease) in tax resulting from:
State taxes, net of federal benefit	1,137,000	(18,492,000)	2,207,000
State net operating loss, net of federal benefit	5,148,000	(7,586,000)	1,544,000
General business credits	243,000	(121,000)	307,000
Valuation allowance	110,575,000	(127,726,000)	912,000
Charitable contributions	66,000	(151,000)	(1,127,000)
Permanent adjustments	1,799,000	1,520,000	(668,000)
Conversion/Exchange of senior debt	0	0	(20,501,000)
Deferred tax adjustment due to REIT conversion	0	0	(688,233,000)
Valuation allowance adjustment due to REIT conversion	0	0	99,626,000
State tax rate change	(2,128,000)	0	0
Effects of federal tax law change	70,676,000	0	0
Asset transfers into TRS	33,735,000	0	0
Other items	(125,000)	5,704,000	(21,000)
Income Tax Expense (Benefit) Including Income Taxes on Gains (Loss) on Disposal of Real Estate	$ (700,000)	$ 53,720,000	$ (581,099,000)
Effective tax rate	(7.45%)	(45.89%)	1172.82%
The components of the deferred income tax expense (benefit) for continuing operations are as follows:
Excess of tax over financial statement depreciation and amortization	$ 1,612,000	$ 2,509,000	$ 2,097,000
Costs on land and rental properties under development expensed for tax purposes	7,121,000	211,000	13,520,000
Revenues and expenses recognized in different periods for tax and financial statement purposes	(26,046,000)	112,205,000	174,072,000
Difference between tax and financial statements related to unconsolidated entities	33,143,000	(104,950,000)	(24,474,000)
Impairment of real estate and land held for divestiture	(15,501,000)	(1,165,000)	(158,002,000)
Deferred state taxes, net of federal benefit	5,350,000	(25,677,000)	2,893,000
Utilization of (addition to) tax loss carryforward excluding effect of stock options	34,387,000	(55,231,000)	(8,566,000)
Valuation allowance	(110,575,000)	127,726,000	(912,000)
General business credits	4,000	121,000	(307,000)
Deferred Tax Adjustment due to REIT Conversion	0	0	(688,233,000)
Valuation Allowance Adjustment Due to REIT Conversion	0	0	99,626,000
Deferred effect of state rate change	(2,128,000)	0	0
Effect of federal tax law change including deferred tax benefit for AMT credit receivable	42,576,000	0	0
Alternative Minimum Tax credits	1,857,000	(1,857,000)	0
Deferred Income Tax Expense (Benefit) Including Deferred Income Taxes on Gains (Losses) on Disposal of Real Estate	(28,200,000)	53,892,000	(588,286,000)
Stand-alone TRSs & other [Member]
Effective tax rate for income taxes from continuing operations
Less: SubREIT, Stand-alone TRS and other earnings (loss)	$ 891,000	$ (3,861,000)	$ 0

Income Taxes (Details 3)

Income Taxes (Details 3) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Components of Deferred Income Tax Asset [Line Items]
Depreciation	$ (2,869,000)	$ (4,257,000)
Capitalized costs	74,054,000	97,886,000
Tax loss carryforward	22,366,000	71,663,000
State loss carryforward, net of federal benefit	9,198,000	12,717,000
Valuation allowance	(169,600,000)	(280,175,000)
Federal tax credits and other carryforwards	232,000	2,632,000
Basis in unconsolidated entities	77,268,000	124,513,000
Other	(10,649,000)	(24,979,000)
Net deferred tax assets	0	0
Temporary Differences [Member]
Components of Deferred Income Tax Asset [Line Items]
Depreciation	(9,843,000)	(10,319,000)
Capitalized costs	254,046,000	237,299,000
Tax loss carryforward	106,505,000	204,752,000
State loss carryforward, net of federal benefit	0	0
Valuation allowance	0	0
Federal tax credits and other carryforwards	0	0
Basis in unconsolidated entities	265,071,000	301,850,000
Other	(47,372,000)	(67,564,000)
Net deferred tax assets	$ 568,407,000	$ 666,018,000

Income Taxes (Details 4)

Income Taxes (Details 4) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Net Deferred Tax Asset
Deferred tax liabilities	$ 116,829,000	$ 182,804,000
Deferred tax assets	286,429,000	462,979,000
Less: valuation allowance	(169,600,000)	(280,175,000)
Net deferred tax assets	116,829,000	182,804,000
Net deferred tax assets	$ 0	$ 0

Income Taxes (Details 5)

Income Taxes (Details 5) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Unrecognized tax benefits
Beginning balance, January 1, 2017 and 2016	$ 187,000	$ 478,000
Settlements	0	0
Lapse of statutes of limitation	0	(291,000)
Unrecognized tax benefits balance at December 31, 2017 and 2016	$ 187,000	$ 187,000

Income Taxes (Details Textual)

Income Taxes (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax Credit Carryforward [Line Items]
Deferred tax adjustment due to REIT conversion	$ 588,607,000
Period after REIT conversion that assets sold are subject to income taxes			5 years
Federal statutory rate			35.00%
Income taxes paid			$ 6,089,000	$ 2,795,000	$ 6,936,000
Federal net operating loss carryforward			106,505,000
Operating Loss Carryforward for REIT tax return			$ 76,176,000
Percentage of AMT tax credits			50.00%
AMT credit receivable			$ 228,419,000	213,887,000
Unrecognized tax benefits			187,000	187,000	478,000
Accrued interest and penalties related to uncertain income tax positions			115,000	103,000
Income tax expense (benefit) relating to interest and penalties on uncertain tax positions			12,000	(69,000)	$ (68,000)
Unrecognized tax benefits that would impact effective tax rate			148,000	122,000
Unrecognized benefits could decrease during the next twelve months			$ 187,000
Period unrecognized tax benefits could decrease			12 months
AMT credit receivable [Member]
Tax Credit Carryforward [Line Items]
AMT credit receivable			$ 28,100,000	$ 0
TRS [Member]
Tax Credit Carryforward [Line Items]
AMT Tax Credit			2,500,000
REIT [Member]
Tax Credit Carryforward [Line Items]
AMT Tax Credit			$ 25,600,000
Scenario, Forecast [Member]
Tax Credit Carryforward [Line Items]
Federal statutory rate		21.00%

Assets and Liabilities Held 141

Assets and Liabilities Held for Sale and Discontinued Operations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of operating results of discontinued operations
Revenues		$ 14,792,000	$ 138,154,000
Expenses
Operating expenses		12,540,000	97,021,000
Depreciation and amortization		23,000	34,554,000
Total expenses		12,563,000	131,575,000
Interest expense	$ 0	(3,540,000)	(40,125,000)
Amortization of mortgage procurement costs		(61,000)	(664,000)
Loss before income taxes and loss from unconsolidated entities		(1,372,000)	(34,210,000)
Loss from unconsolidated entities		(1,400,000)	(40,760,000)
Loss before income taxes		(2,772,000)	(74,970,000)
Income tax expense (benefit)		(824,000)	(22,498,000)
Loss before gain on disposal group		(1,948,000)	(52,472,000)
Gain on disposition of disposal group, net of tax	0	49,353,000	0
Earnings (loss) from discontinued operations	0	47,405,000	(52,472,000)
Noncontrolling interests
Operating loss from disposal group and rental properties	$ 0	(776,000)	(16,962,000)
Earnings (loss) from discontinued operations attributable to Forest City Realty Trust, Inc.		$ 48,181,000	$ (35,510,000)

Assets and Liabilities Held 142

Assets and Liabilities Held for Sale and Discontinued Operations (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Pre-tax gain (loss) on disposition of disposal group		$ 79,766,000	$ 0
Income tax effect on gain (loss) on disposition of disposal group		(30,413,000)	0
Gain on disposition of disposal group, net of tax	$ 0	49,353,000	0
The Nets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Pre-tax gain (loss) on disposition of disposal group		136,247,000	0
Barclays Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Pre-tax gain (loss) on disposition of disposal group		$ (56,481,000)	$ 0

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Numerators
Earnings (loss) from continuing operations attributable to Forest City Realty Trust, Inc.		$ 206,030,000	$ (206,583,000)	$ 531,552,000
Distributed and undistributed earnings allocated to participating securities		(1,677,000)	0	(10,410,000)
Earnings (loss) from continuing operations attributable to common shareholders - Basic		204,353,000	(206,583,000)	521,142,000
Undistributed Earnings from Continuing Operations Allocated to Participating Securities Diluted		506,000	0	0
Preferred Distribution on Common Stock Units		709,000	0	0
Interest on convertible debt		0	0	6,606,000
Earnings (loss) from continuing operations attributable to common stockholders - Diluted		205,568,000	(206,583,000)	527,748,000
Net earnings (loss) attributable to Forest City Realty Trust, Inc.		206,030,000	(158,402,000)	496,042,000
Distributed and undistributed earnings allocated to participating securities		1,677,000	0	9,715,000
Net earnings (loss) attributable to common stockholders - Basic		204,353,000	(158,402,000)	486,327,000
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted		506,000	0	0
Net earnings (loss) attributable to common stockholders - Diluted		$ 205,568,000	$ (158,402,000)	$ 492,933,000
Denominators
Weighted average shares outstanding - Basic		262,510,532	258,509,970	237,559,598
Effect of stock options and performance shares		763,611	0	1,342,524
Effect of convertible Class A Common Units		1,594,238	0	0
Effect of convertible debt		0	0	11,946,164
Weighted average shares outstanding - Diluted	[1]	264,868,381	258,509,970	250,848,286
Earnings Per Share [Abstract]
Earnings (loss) from continuing operations attributable to common stockholders - Basic		$ 0.78	$ (0.80)	$ 2.19
Earnings (loss) from continuing operations attributable to common stockholders - Diluted		0.78	(0.80)	2.10
Net earnings (loss) attributable to common stockholders - Basic		0.78	(0.61)	2.05
Net earnings (loss) attributable to common stockholders - Diluted		$ 0.78	$ (0.61)	$ 1.97
[1]	(1)Incremental shares from restricted stock and convertible securities aggregating 5,923,113 and 9,706,419 for the years ended December 31, 2017 and 2015, respectively, were not included in the computation of diluted EPS because their effect is anti-dilutive. Incremental shares from dilutive options, restricted stock, performance shares and convertible securities aggregating 9,528,889 for the year ended December 31, 2016 were not included in the computation of diluted EPS because their effect is anti-dilutive due to loss from continuing operations. Weighted-average options, restricted stock and performance shares of 1,333,046, 2,706,145 and 2,392,982 for the years ended December 31, 2017, 2016 and 2015, respectively, were not included in the computation of diluted EPS because their effect is anti-dilutive under the treasury stock method.

Earnings Per Share (Details Tex

Earnings Per Share (Details Textual) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted stock and convertible securities [Member]
Earnings Per Share (Textual) [Abstract]
Shares excluded from computation of earnings per share	5,923,113		9,706,419
Dilutive Options Restricted Stock and Convertible Securities [Member]
Earnings Per Share (Textual) [Abstract]
Shares excluded from computation of earnings per share		9,528,889
Weighted-average options, restricted stock and performance shares [Member]
Earnings Per Share (Textual) [Abstract]
Shares excluded from computation of earnings per share	1,333,046	2,706,145	2,392,982

Segment Information (Details)

Segment Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financial data of reportable operating segments
Identifiable assets	$ 8,063,287,000	$ 8,228,597,000
Revenues	911,926,000	929,483,000	$ 978,231,000
Operating Expenses	522,292,000	553,576,000	625,352,000
Depreciation and amortization	248,353,000	250,848,000	252,925,000
Capital expenditures	435,841,000	576,556,000	536,569,000
Office [Member]
Financial data of reportable operating segments
Identifiable assets	3,025,810,000	3,192,840,000
Revenues	449,636,000	463,855,000	425,052,000
Operating Expenses	169,792,000	185,983,000	182,677,000
Depreciation and amortization	125,825,000	134,323,000	109,176,000
Capital expenditures	58,235,000	40,066,000	56,354,000
Apartments [Member]
Financial data of reportable operating segments
Identifiable assets	2,246,479,000	2,406,768,000
Revenues	286,358,000	291,615,000	267,633,000
Operating Expenses	126,317,000	137,313,000	142,926,000
Depreciation and amortization	77,956,000	77,556,000	78,593,000
Capital expenditures	29,569,000	19,383,000	27,722,000
Retail [Member]
Financial data of reportable operating segments
Identifiable assets	368,353,000	521,015,000
Revenues	53,335,000	79,660,000	138,955,000
Operating Expenses	37,710,000	52,127,000	90,489,000
Depreciation and amortization	9,343,000	20,662,000	51,326,000
Capital expenditures	4,608,000	9,885,000	9,999,000
Total Operations [Member]
Financial data of reportable operating segments
Identifiable assets	5,640,642,000	6,120,623,000
Revenues	789,329,000	835,130,000	831,640,000
Operating Expenses	333,819,000	375,423,000	416,092,000
Depreciation and amortization	213,124,000	232,541,000	239,095,000
Capital expenditures	92,412,000	69,334,000	94,075,000
Development [Member]
Financial data of reportable operating segments
Identifiable assets	2,020,273,000	1,799,138,000
Revenues	122,597,000	90,835,000	114,722,000
Operating Expenses	91,929,000	81,032,000	101,031,000
Depreciation and amortization	32,603,000	16,902,000	10,481,000
Capital expenditures	333,211,000	507,123,000	442,289,000
Corporate [Member]
Financial data of reportable operating segments
Identifiable assets	402,372,000	308,836,000
Revenues	0	0	0
Operating Expenses	96,544,000	94,391,000	100,099,000
Depreciation and amortization	2,626,000	1,279,000	2,582,000
Capital expenditures	10,218,000	99,000	205,000
Other [Member]
Financial data of reportable operating segments
Revenues	0	3,518,000	31,869,000
Operating Expenses	0	2,730,000	8,130,000
Depreciation and amortization	0	126,000	767,000
Capital expenditures	$ 0	$ 0	$ 0

Segment Information (Details 1)

Segment Information (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Net Earnings (Loss) to FFO by Segment
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	$ 206,030,000	$ (158,402,000)	$ 496,042,000
Depreciation and amortization	248,353,000	250,848,000	252,925,000
Interest Expense	120,431,000	131,441,000	157,166,000
Amortization of mortgage procurement costs	5,550,000	5,719,000	7,549,000
Income tax expense (benefit)	(21,614,000)	3,733,000	(581,778,000)
Reclassification adjustment for interest rate swap breakage fee	0	(24,635,000)	0
Impairment of consolidated real estate	44,288,000	156,825,000	451,434,000
Loss on extinguishment of debt	(2,961,000)	(32,960,000)	(65,086,000)
Net (gain) loss on disposition of full or partial interest in development project	(113,000)	136,117,000	0
Net (gain) loss on disposition of full or partial interest in rental properties	18,800,000	121,284,000	1,067,000
Gain on disposition of unconsolidated entities	110,221,000	13,166,000	20,293,000
Gain on change in control of interests	0	0	486,279,000
Organizational transformation and termination benefits	34,395,000	31,708,000	48,125,000
Discontinued operations:
(Gain) loss on disposition of rental properties		(79,766,000)	0
Nets pre-tax EBIDTA	25,163,000	29,701,000	22,313,000
The Nets [Member]
Discontinued operations:
(Gain) loss on disposition of rental properties		(136,247,000)	0
Adjusted EBIDTA [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	206,030,000	(158,402,000)	496,042,000
Interest Expense	198,777,000	221,812,000	264,299,000
Amortization of mortgage procurement costs	7,469,000	8,680,000	10,600,000
Income tax expense (benefit)	(21,422,000)	85,105,000	(603,597,000)
Reclassification adjustment for interest rate swap breakage fee		24,635,000
Impairment of consolidated real estate	44,288,000	156,825,000	451,434,000
Impairment of unconsolidated real estate	10,600,000	306,400,000	13,844,000
Loss on extinguishment of debt	4,514,000	33,863,000	65,103,000
Net (gain) loss on disposition of full or partial interest in development project		(136,687,000)
Net (gain) loss on disposition of full or partial interest in rental properties	(46,121,000)	(172,682,000)	(1,746,000)
Gain on disposition of unconsolidated entities	(108,837,000)	(13,166,000)	(20,293,000)
Gain on change in control of interests			(486,279,000)
Organizational transformation and termination benefits	34,395,000	31,708,000	48,125,000
Discontinued operations:
Depreciation and amortization - Real Estate		35,000	20,104,000
(Gain) loss on disposition of rental properties		(56,481,000)
Nets pre-tax EBIDTA		1,400,000	40,760,000
Adjusted EBIDTA Attributable to Forest City Realty Trust, Inc.	643,078,000	631,474,000	620,597,000
Adjusted EBIDTA [Member] | The Nets [Member]
Discontinued operations:
(Gain) loss on disposition of rental properties		136,247,000
Adjusted EBIDTA [Member] | Adjusted EBIDTA Depreciation [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Depreciation and amortization	313,385,000	321,714,000	322,201,000
Office [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	165,040,000	138,282,000	576,328,000
Depreciation and amortization	125,825,000	134,323,000	109,176,000
Interest Expense	0	0	0
Amortization of mortgage procurement costs	0	0	0
Income tax expense (benefit)	0	0	0
Reclassification adjustment for interest rate swap breakage fee		0
Impairment of consolidated real estate	0	19,700,000	28,146,000
Impairment of unconsolidated real estate	0	0	0
Loss on extinguishment of debt	0	0	0
Net (gain) loss on disposition of full or partial interest in development project		0
Net (gain) loss on disposition of full or partial interest in rental properties	(2,589,000)	(13,782,000)	(1,746,000)
Gain on disposition of unconsolidated entities	(1,437,000)	0	(1,009,000)
Gain on change in control of interests			(463,643,000)
Organizational transformation and termination benefits	0	0	0
Discontinued operations:
Depreciation and amortization - Real Estate		0	0
(Gain) loss on disposition of rental properties		0
Nets pre-tax EBIDTA		0	0
Adjusted EBIDTA Attributable to Forest City Realty Trust, Inc.	290,216,000	278,711,000	250,901,000
Office [Member] | The Nets [Member]
Discontinued operations:
(Gain) loss on disposition of rental properties		0
Office [Member] | Adjusted EBIDTA Depreciation [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Depreciation and amortization	129,202,000	134,511,000	112,825,000
Apartments [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	179,036,000	102,249,000	82,944,000
Depreciation and amortization	77,956,000	77,556,000	78,593,000
Interest Expense	0	0	0
Amortization of mortgage procurement costs	0	0	0
Income tax expense (benefit)	0	0	0
Reclassification adjustment for interest rate swap breakage fee		0
Impairment of consolidated real estate	0	2,100,000	8,423,000
Impairment of unconsolidated real estate	0	0	12,460,000
Loss on extinguishment of debt	0	0	0
Net (gain) loss on disposition of full or partial interest in development project		0
Net (gain) loss on disposition of full or partial interest in rental properties	(6,065,000)	(2,333,000)	0
Gain on disposition of unconsolidated entities	(71,037,000)	0	(19,284,000)
Gain on change in control of interests			(24,041,000)
Organizational transformation and termination benefits	0	0	0
Discontinued operations:
Depreciation and amortization - Real Estate		0	0
(Gain) loss on disposition of rental properties		0
Nets pre-tax EBIDTA		0	0
Adjusted EBIDTA Attributable to Forest City Realty Trust, Inc.	191,819,000	196,638,000	151,880,000
Apartments [Member] | The Nets [Member]
Discontinued operations:
(Gain) loss on disposition of rental properties		0
Apartments [Member] | Adjusted EBIDTA Depreciation [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Depreciation and amortization	89,885,000	94,622,000	91,378,000
Retail [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	152,698,000	(15,813,000)	(321,052,000)
Depreciation and amortization	9,343,000	20,662,000	51,326,000
Interest Expense	0	0	0
Amortization of mortgage procurement costs	0	0	0
Income tax expense (benefit)	0	0	0
Reclassification adjustment for interest rate swap breakage fee		0
Impairment of consolidated real estate	0	133,795,000	398,558,000
Impairment of unconsolidated real estate	10,600,000	0	0
Loss on extinguishment of debt	0	0	0
Net (gain) loss on disposition of full or partial interest in development project		0
Net (gain) loss on disposition of full or partial interest in rental properties	(37,467,000)	(15,216,000)	0
Gain on disposition of unconsolidated entities	(36,363,000)	(12,613,000)	0
Gain on change in control of interests			0
Organizational transformation and termination benefits	0	0	0
Discontinued operations:
Depreciation and amortization - Real Estate		0	0
(Gain) loss on disposition of rental properties		0
Nets pre-tax EBIDTA		0	0
Adjusted EBIDTA Attributable to Forest City Realty Trust, Inc.	154,520,000	168,971,000	177,392,000
Retail [Member] | The Nets [Member]
Discontinued operations:
(Gain) loss on disposition of rental properties		0
Retail [Member] | Adjusted EBIDTA Depreciation [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Depreciation and amortization	65,052,000	78,818,000	99,886,000
Total Operations [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	496,774,000	224,718,000	338,220,000
Depreciation and amortization	213,124,000	232,541,000	239,095,000
Interest Expense	0	0	0
Amortization of mortgage procurement costs	0	0	0
Income tax expense (benefit)	0	0	0
Reclassification adjustment for interest rate swap breakage fee		0
Impairment of consolidated real estate	0	155,595,000	435,127,000
Impairment of unconsolidated real estate	10,600,000	0	12,460,000
Loss on extinguishment of debt	0	0	0
Net (gain) loss on disposition of full or partial interest in development project		0
Net (gain) loss on disposition of full or partial interest in rental properties	(46,121,000)	(31,331,000)	(1,746,000)
Gain on disposition of unconsolidated entities	(108,837,000)	(12,613,000)	(20,293,000)
Gain on change in control of interests			(487,684,000)
Organizational transformation and termination benefits	0	0	0
Discontinued operations:
Depreciation and amortization - Real Estate		0	0
(Gain) loss on disposition of rental properties		0
Nets pre-tax EBIDTA		0	0
Adjusted EBIDTA Attributable to Forest City Realty Trust, Inc.	636,555,000	644,320,000	580,173,000
Total Operations [Member] | The Nets [Member]
Discontinued operations:
(Gain) loss on disposition of rental properties		0
Total Operations [Member] | Adjusted EBIDTA Depreciation [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Depreciation and amortization	284,139,000	307,951,000	304,089,000
Development [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	(59,398,000)	(182,716,000)	(26,107,000)
Depreciation and amortization	32,603,000	16,902,000	10,481,000
Interest Expense	0	0	0
Amortization of mortgage procurement costs	0	0	0
Income tax expense (benefit)	0	0	0
Reclassification adjustment for interest rate swap breakage fee		0
Impairment of consolidated real estate	44,288,000	1,230,000	16,307,000
Impairment of unconsolidated real estate	0	306,400,000	1,384,000
Loss on extinguishment of debt	0	0	0
Net (gain) loss on disposition of full or partial interest in development project		(136,687,000)
Net (gain) loss on disposition of full or partial interest in rental properties	0	324,000	0
Gain on disposition of unconsolidated entities	0	(553,000)	0
Gain on change in control of interests			1,405,000
Organizational transformation and termination benefits	0	0	0
Discontinued operations:
Depreciation and amortization - Real Estate		0	0
(Gain) loss on disposition of rental properties		0
Nets pre-tax EBIDTA		0	0
Adjusted EBIDTA Attributable to Forest City Realty Trust, Inc.	11,510,000	180,000	5,722,000
Development [Member] | The Nets [Member]
Discontinued operations:
(Gain) loss on disposition of rental properties		0
Development [Member] | Adjusted EBIDTA Depreciation [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Depreciation and amortization	26,620,000	12,182,000	12,733,000
Corporate [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	(231,346,000)	(422,592,000)	198,327,000
Depreciation and amortization	2,626,000	1,279,000	2,582,000
Interest Expense	198,777,000	221,812,000	264,299,000
Amortization of mortgage procurement costs	7,469,000	8,680,000	10,600,000
Income tax expense (benefit)	(21,422,000)	85,105,000	(603,597,000)
Reclassification adjustment for interest rate swap breakage fee		24,635,000
Impairment of consolidated real estate	0	0	0
Impairment of unconsolidated real estate	0	0	0
Loss on extinguishment of debt	4,514,000	33,863,000	65,103,000
Net (gain) loss on disposition of full or partial interest in development project		0
Net (gain) loss on disposition of full or partial interest in rental properties	0	0	0
Gain on disposition of unconsolidated entities	0	0	0
Gain on change in control of interests			0
Organizational transformation and termination benefits	34,395,000	31,708,000	48,125,000
Discontinued operations:
Depreciation and amortization - Real Estate		0	0
(Gain) loss on disposition of rental properties		0
Nets pre-tax EBIDTA		0	0
Adjusted EBIDTA Attributable to Forest City Realty Trust, Inc.	(4,987,000)	(15,510,000)	(14,561,000)
Corporate [Member] | The Nets [Member]
Discontinued operations:
(Gain) loss on disposition of rental properties		0
Corporate [Member] | Adjusted EBIDTA Depreciation [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Depreciation and amortization	2,626,000	1,279,000	2,582,000
Other [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Net earnings (loss) attributable to Forest City Realty Trust, Inc.	0	222,188,000	(14,398,000)
Depreciation and amortization	0	126,000	767,000
Interest Expense	0	0	0
Amortization of mortgage procurement costs	0	0	0
Income tax expense (benefit)	0	0	0
Reclassification adjustment for interest rate swap breakage fee		0
Impairment of consolidated real estate	0	0	0
Impairment of unconsolidated real estate	0	0	0
Loss on extinguishment of debt	0	0	0
Net (gain) loss on disposition of full or partial interest in development project		0
Net (gain) loss on disposition of full or partial interest in rental properties		(141,675,000)	0
Gain on disposition of unconsolidated entities	0	0	0
Gain on change in control of interests			0
Organizational transformation and termination benefits	0	0	0
Discontinued operations:
Depreciation and amortization - Real Estate		35,000	20,104,000
(Gain) loss on disposition of rental properties		(56,481,000)
Nets pre-tax EBIDTA		1,400,000	40,760,000
Adjusted EBIDTA Attributable to Forest City Realty Trust, Inc.	0	2,484,000	49,263,000
Other [Member] | The Nets [Member]
Discontinued operations:
(Gain) loss on disposition of rental properties		136,247,000
Other [Member] | Adjusted EBIDTA Depreciation [Member]
Reconciliation of Net Earnings (Loss) to FFO by Segment
Depreciation and amortization	$ 0	$ 302,000	$ 2,797,000

Segment Information Segments (D

Segment Information Segments (Details Textuals)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Occupancy rate of stabilized properties	92.00%
Stabilization, minimum years open and operating	1 year
Stabilization, maximum years open and operating	2 years

Subsequent Event Subsequent 148

Subsequent Event Subsequent Event (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Cash received for amendment of partnership		$ 0	$ 0	$ 486,279,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Ownership percentage of outside partner	50.00%
Cash received for amendment of partnership	$ 24,000,000

Valuation and Qualifying Acc149

Valuation and Qualifying Accounts (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Allowance for doubtful accounts receivable [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 5,324,000		$ 9,025,000		$ 10,771,000
Additions Charged to Costs and Expenses	343,000		1,628,000		2,744,000
Deductions	2,270,000		5,329,000		4,490,000
Balance at End of Period	3,397,000		5,324,000		9,025,000
Valuation reserve on other investments [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	5,355,000		5,336,000		5,320,000
Additions Charged to Costs and Expenses	10,000		19,000		16,000
Deductions	25,000		0		0
Balance at End of Period	5,340,000		5,355,000		5,336,000
Valuation allowances for deferred tax assets [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	280,175,000	[1]	152,449,000		53,735,000
Additions Charged to Costs and Expenses	13,466,000	[1]	163,330,000		145,351,000
Deductions	124,041,000	[1]	35,604,000		46,637,000
Balance at End of Period	$ 169,600,000	[1]	$ 280,175,000	[1]	$ 152,449,000
[1]	(1) See Note V – Income Taxes in the Notes to Consolidated Financial Statements in Item 8 of this Form 10-K for additional information.

Real Estate and Accumulated 150

Real Estate and Accumulated Depreciation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 2,998,361,000
Initial Cost to Company, Land and Improvements	645,328,000
Initial Cost to Company, Buildings and Improvements	6,145,837,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	989,290,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	771,183,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	7,009,272,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	7,780,455,000	$ 7,915,565,000	$ 9,613,342,000	$ 8,328,987,000
Accumulated Depreciation at December 31, 2017	1,484,163,000	$ 1,442,006,000	$ 1,734,382,000	$ 1,555,965,000
Office [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	1,009,905,000
Initial Cost to Company, Land and Improvements	139,918,000
Initial Cost to Company, Buildings and Improvements	2,782,881,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	563,081,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	236,033,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	3,249,847,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	3,485,880,000
Accumulated Depreciation at December 31, 2017	823,907,000
Office [Member] | Atlantic Terminal Office [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	102,542,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	108,940,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	6,131,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	115,071,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	115,071,000
Accumulated Depreciation at December 31, 2017	$ 30,743,000
Date of Construction/Acquisition	Dec. 31, 2004
Office [Member] | Ballston Common Office Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	7,301,000
Initial Cost to Company, Buildings and Improvements	45,964,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	7,395,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	7,301,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	53,359,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	60,660,000
Accumulated Depreciation at December 31, 2017	$ 11,957,000
Date of Construction/Acquisition	Dec. 31, 2005
Office [Member] | Edgeworth Building [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 19,597,000
Initial Cost to Company, Land and Improvements	942,000
Initial Cost to Company, Buildings and Improvements	29,353,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	4,002,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	951,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	33,346,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	34,297,000
Accumulated Depreciation at December 31, 2017	$ 7,222,000
Date of Construction/Acquisition	Dec. 31, 2006
Office [Member] | Glen Forest Office Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 59,131,000
Initial Cost to Company, Land and Improvements	11,766,000
Initial Cost to Company, Buildings and Improvements	88,632,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	15,515,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	11,841,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	104,072,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	115,913,000
Accumulated Depreciation at December 31, 2017	$ 29,678,000
Date of Construction/Acquisition	Dec. 31, 2007
Office [Member] | Harlem Office [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	31,672,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	8,422,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	40,094,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	40,094,000
Accumulated Depreciation at December 31, 2017	$ 10,745,000
Date of Construction/Acquisition	Dec. 31, 2003
Office [Member] | Johns Hopkins - 855 North Wolfe Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 64,085,000
Initial Cost to Company, Land and Improvements	7,314,000
Initial Cost to Company, Buildings and Improvements	76,318,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	23,413,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	7,314,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	99,731,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	107,045,000
Accumulated Depreciation at December 31, 2017	$ 20,032,000
Date of Construction/Acquisition	Dec. 31, 2008
Office [Member] | Johns Hopkins Parking Garage [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	835,000
Initial Cost to Company, Buildings and Improvements	13,674,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,503,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	835,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	15,177,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	16,012,000
Accumulated Depreciation at December 31, 2017	$ 1,531,000
Date of Construction/Acquisition	Dec. 31, 2012
Office [Member] | Fidelity Investments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 12,230,000
Initial Cost to Company, Land and Improvements	5,003,000
Initial Cost to Company, Buildings and Improvements	29,872,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	293,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	5,003,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	30,165,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	35,168,000
Accumulated Depreciation at December 31, 2017	$ 5,603,000
Date of Construction/Acquisition	Dec. 31, 2008
Office [Member] | One MetroTech Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	212,153,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	72,803,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	23,543,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	261,413,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	284,956,000
Accumulated Depreciation at December 31, 2017	$ 134,904,000
Date of Construction/Acquisition	Dec. 31, 1991
Office [Member] | Two MetroTech Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 68,941,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	155,280,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	34,932,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	7,137,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	183,075,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	190,212,000
Accumulated Depreciation at December 31, 2017	$ 92,843,000
Date of Construction/Acquisition	Dec. 31, 1990
Office [Member] | Nine MetroTech Center North [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 55,196,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	64,303,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	13,510,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	380,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	77,433,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	77,813,000
Accumulated Depreciation at December 31, 2017	$ 29,796,000
Date of Construction/Acquisition	Dec. 31, 1997
Office [Member] | Eleven MetroTech Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	41,290,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	25,554,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	6,270,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	60,574,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	66,844,000
Accumulated Depreciation at December 31, 2017	$ 30,510,000
Date of Construction/Acquisition	Dec. 31, 1995
Office [Member] | Twelve MetroTech Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	42,344,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	16,092,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,847,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	56,589,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	58,436,000
Accumulated Depreciation at December 31, 2017	$ 15,279,000
Date of Construction/Acquisition	Dec. 31, 2004
Office [Member] | Fifteen MetroTech Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 154,848,000
Initial Cost to Company, Land and Improvements	3,762,000
Initial Cost to Company, Buildings and Improvements	163,414,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	8,482,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	175,658,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	175,658,000
Accumulated Depreciation at December 31, 2017	$ 49,455,000
Date of Construction/Acquisition	Dec. 31, 2003
Office [Member] | New York Times [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	91,737,000
Initial Cost to Company, Buildings and Improvements	375,931,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	138,494,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	141,479,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	464,683,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	606,162,000
Accumulated Depreciation at December 31, 2017	$ 95,791,000
Date of Construction/Acquisition	Dec. 31, 2007
Office [Member] | One Pierrepont Plaza [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	86,863,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	108,715,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	558,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	195,020,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	195,578,000
Accumulated Depreciation at December 31, 2017	$ 120,714,000
Date of Construction/Acquisition	Dec. 31, 1988
Office [Member] | Commerce Court [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 22,710,000
Initial Cost to Company, Land and Improvements	3,432,000
Initial Cost to Company, Buildings and Improvements	20,873,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	9,243,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	3,441,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	30,107,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	33,548,000
Accumulated Depreciation at December 31, 2017	$ 10,861,000
Date of Construction/Acquisition	Dec. 31, 2007
Office [Member] | Landmark Building [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 25,140,000
Initial Cost to Company, Land and Improvements	5,989,000
Initial Cost to Company, Buildings and Improvements	27,519,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	13,643,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	15,919,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	31,232,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	47,151,000
Accumulated Depreciation at December 31, 2017	$ 15,262,000
Date of Construction/Acquisition	Dec. 31, 1994
Office [Member] | University of Pennsylvania [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 35,788,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	41,146,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	10,707,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	51,853,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	51,853,000
Accumulated Depreciation at December 31, 2017	$ 13,506,000
Date of Construction/Acquisition	Dec. 31, 2004
Office [Member] | 26 Landsdowne [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 27,208,000
Initial Cost to Company, Land and Improvements	90,000
Initial Cost to Company, Buildings and Improvements	79,470,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,866,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	135,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	81,291,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	81,426,000
Accumulated Depreciation at December 31, 2017	$ 5,397,000
Date of Construction/Acquisition	Dec. 31, 1987
Office [Member] | 35 Landsdowne [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 62,676,000
Initial Cost to Company, Land and Improvements	196,000
Initial Cost to Company, Buildings and Improvements	181,779,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	770,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	258,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	182,487,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	182,745,000
Accumulated Depreciation at December 31, 2017	$ 13,313,000
Date of Construction/Acquisition	Dec. 31, 2002
Office [Member] | 40 Landsdowne [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 63,581,000
Initial Cost to Company, Land and Improvements	236,000
Initial Cost to Company, Buildings and Improvements	192,897,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,787,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	301,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	194,619,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	194,920,000
Accumulated Depreciation at December 31, 2017	$ 14,273,000
Date of Construction/Acquisition	Dec. 31, 2003
Office [Member] | 45/75 Sidney Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 85,891,000
Initial Cost to Company, Land and Improvements	793,000
Initial Cost to Company, Buildings and Improvements	289,942,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	22,656,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	877,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	312,514,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	313,391,000
Accumulated Depreciation at December 31, 2017	$ 22,302,000
Date of Construction/Acquisition	Dec. 31, 1999
Office [Member] | 64 Sidney Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 50,624,000
Initial Cost to Company, Land and Improvements	50,000
Initial Cost to Company, Buildings and Improvements	110,850,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	4,744,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	89,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	115,555,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	115,644,000
Accumulated Depreciation at December 31, 2017	$ 11,084,000
Date of Construction/Acquisition	Dec. 31, 1990
Office [Member] | 65 Landsdowne [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 63,919,000
Initial Cost to Company, Land and Improvements	198,000
Initial Cost to Company, Buildings and Improvements	125,278,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	99,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	236,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	125,339,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	125,575,000
Accumulated Depreciation at December 31, 2017	$ 8,545,000
Date of Construction/Acquisition	Dec. 31, 2001
Office [Member] | 88 Sidney Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 35,798,000
Initial Cost to Company, Land and Improvements	274,000
Initial Cost to Company, Buildings and Improvements	145,426,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	490,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	318,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	145,872,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	146,190,000
Accumulated Depreciation at December 31, 2017	$ 13,028,000
Date of Construction/Acquisition	Dec. 31, 2002
Office [Member] | Miscellaneous Investments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	1,698,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	11,820,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	13,518,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	13,518,000
Accumulated Depreciation at December 31, 2017	9,533,000
Retail [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	47,209,000
Initial Cost to Company, Land and Improvements	3,457,000
Initial Cost to Company, Buildings and Improvements	64,103,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	36,430,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	28,411,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	75,579,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	103,990,000
Accumulated Depreciation at December 31, 2017	25,992,000
Retail [Member] | Miscellaneous Investments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	1,646,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	1,818,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	1,818,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	1,818,000
Accumulated Depreciation at December 31, 2017	1,783,000
Retail [Member] | Brooklyn Commons [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	17,143,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	23,794,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,289,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	19,618,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	5,465,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	25,083,000
Accumulated Depreciation at December 31, 2017	$ 2,226,000
Date of Construction/Acquisition	Dec. 31, 2004
Retail [Member] | Shops at Atlantic Center Site V [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	3,238,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,485,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,047,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	3,676,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	4,723,000
Accumulated Depreciation at December 31, 2017	$ 1,603,000
Date of Construction/Acquisition	Dec. 31, 1998
Retail [Member] | Station Square [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 7,540,000
Initial Cost to Company, Land and Improvements	2,622,000
Initial Cost to Company, Buildings and Improvements	9,965,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	25,710,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	6,913,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	31,384,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	38,297,000
Accumulated Depreciation at December 31, 2017	$ 17,020,000
Date of Construction/Acquisition	Dec. 31, 1994
Retail [Member] | Boilermaker Shops [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 11,135,000
Initial Cost to Company, Land and Improvements	529,000
Initial Cost to Company, Buildings and Improvements	12,468,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	6,446,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	527,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	18,916,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	19,443,000
Accumulated Depreciation at December 31, 2017	$ 1,895,000
Date of Construction/Acquisition	Dec. 31, 2012
Retail [Member] | Lumber Shed [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 9,745,000
Initial Cost to Company, Land and Improvements	306,000
Initial Cost to Company, Buildings and Improvements	12,820,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,500,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	306,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	14,320,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	14,626,000
Accumulated Depreciation at December 31, 2017	$ 1,465,000
Date of Construction/Acquisition	Dec. 31, 2013
Apartments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 1,363,784,000
Initial Cost to Company, Land and Improvements	267,138,000
Initial Cost to Company, Buildings and Improvements	1,990,887,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	292,047,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	267,869,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	2,282,203,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	2,550,072,000
Accumulated Depreciation at December 31, 2017	582,485,000
Apartments [Member] | Miscellaneous Investments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	1,595,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	2,995,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	18,638,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	21,633,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	21,633,000
Accumulated Depreciation at December 31, 2017	13,922,000
Apartments [Member] | 100 (100 Landsdowne) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	44,117,000
Initial Cost to Company, Land and Improvements	728,000
Initial Cost to Company, Buildings and Improvements	60,020,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	951,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	892,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	60,807,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	61,699,000
Accumulated Depreciation at December 31, 2017	$ 18,119,000
Date of Construction/Acquisition	Dec. 31, 2005
Apartments [Member] | 1111 Stratford [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	2,414,000
Initial Cost to Company, Buildings and Improvements	15,798,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	5,553,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	2,518,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	21,247,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	23,765,000
Accumulated Depreciation at December 31, 2017	$ 3,764,000
Date of Construction/Acquisition	Dec. 31, 2013
Apartments [Member] | 1251 S. Michigan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 9,498,000
Initial Cost to Company, Land and Improvements	97,000
Initial Cost to Company, Buildings and Improvements	13,978,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,091,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	106,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	15,060,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	15,166,000
Accumulated Depreciation at December 31, 2017	$ 4,129,000
Date of Construction/Acquisition	Dec. 31, 2006
Apartments [Member] | 2175 Market Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 29,803,000
Initial Cost to Company, Land and Improvements	3,793,000
Initial Cost to Company, Buildings and Improvements	34,508,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	921,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	3,855,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	35,367,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	39,222,000
Accumulated Depreciation at December 31, 2017	$ 4,691,000
Date of Construction/Acquisition	Dec. 31, 2014
Apartments [Member] | 91 Sidney [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 28,921,000
Initial Cost to Company, Land and Improvements	213,000
Initial Cost to Company, Buildings and Improvements	42,276,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,362,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	269,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	43,582,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	43,851,000
Accumulated Depreciation at December 31, 2017	$ 5,114,000
Date of Construction/Acquisition	Dec. 31, 2002
Apartments [Member] | American Cigar Lofts [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 11,259,000
Initial Cost to Company, Land and Improvements	1,395,000
Initial Cost to Company, Buildings and Improvements	23,533,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,870,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	855,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	25,943,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	26,798,000
Accumulated Depreciation at December 31, 2017	$ 6,362,000
Date of Construction/Acquisition	Dec. 31, 2000
Apartments [Member] | Aster Conservatory Green [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 35,806,000
Initial Cost to Company, Land and Improvements	1,325,000
Initial Cost to Company, Buildings and Improvements	13,125,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	33,301,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,599,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	46,152,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	47,751,000
Accumulated Depreciation at December 31, 2017	$ 7,774,000
Date of Construction/Acquisition	Dec. 31, 2013
Apartments [Member] | Aster Town Center North [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 17,629,000
Initial Cost to Company, Land and Improvements	611,000
Initial Cost to Company, Buildings and Improvements	20,705,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	611,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	20,705,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	21,316,000
Accumulated Depreciation at December 31, 2017	$ 1,970,000
Date of Construction/Acquisition	Dec. 31, 2015
Apartments [Member] | Bayside Village [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 126,896,000
Initial Cost to Company, Land and Improvements	153,894,000
Initial Cost to Company, Buildings and Improvements	282,807,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	3,333,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	153,576,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	286,458,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	440,034,000
Accumulated Depreciation at December 31, 2017	$ 24,961,000
Date of Construction/Acquisition	Dec. 31, 1988
Apartments [Member] | Botanica Eastbridge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 12,610,000
Initial Cost to Company, Land and Improvements	765,000
Initial Cost to Company, Buildings and Improvements	13,698,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	542,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	772,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	14,233,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	15,005,000
Accumulated Depreciation at December 31, 2017	$ 2,837,000
Date of Construction/Acquisition	Dec. 31, 2012
Apartments [Member] | Cameron Kinney Lofts [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	2,340,000
Initial Cost to Company, Buildings and Improvements	23,206,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	4,126,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	2,502,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	27,170,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	29,672,000
Accumulated Depreciation at December 31, 2017	$ 7,123,000
Date of Construction/Acquisition	Dec. 31, 2007
Apartments [Member] | Cedar Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 3,585,000
Initial Cost to Company, Land and Improvements	399,000
Initial Cost to Company, Buildings and Improvements	7,000,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	558,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	399,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	7,558,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	7,957,000
Accumulated Depreciation at December 31, 2017	$ 4,569,000
Date of Construction/Acquisition	Dec. 31, 1974
Apartments [Member] | Cherry Tree [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 16,231,000
Initial Cost to Company, Land and Improvements	4,838,000
Initial Cost to Company, Buildings and Improvements	22,028,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	979,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	4,839,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	23,006,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	27,845,000
Accumulated Depreciation at December 31, 2017	$ 2,952,000
Date of Construction/Acquisition	Dec. 31, 1996
Apartments [Member] | Chestnut Lake [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 21,950,000
Initial Cost to Company, Land and Improvements	5,494,000
Initial Cost to Company, Buildings and Improvements	16,466,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	10,882,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	5,684,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	27,158,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	32,842,000
Accumulated Depreciation at December 31, 2017	$ 3,060,000
Date of Construction/Acquisition	Dec. 31, 1969
Apartments [Member] | Consolidated-Carolina Lofts [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 20,623,000
Initial Cost to Company, Land and Improvements	1,028,000
Initial Cost to Company, Buildings and Improvements	30,425,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	2,145,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,046,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	32,552,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	33,598,000
Accumulated Depreciation at December 31, 2017	$ 10,016,000
Date of Construction/Acquisition	Dec. 31, 2003
Apartments [Member] | Cutter's Ridge [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	389,000
Initial Cost to Company, Buildings and Improvements	4,356,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	(93,000)
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	400,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	4,252,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	4,652,000
Accumulated Depreciation at December 31, 2017	$ 1,492,000
Date of Construction/Acquisition	Dec. 31, 2006
Apartments [Member] | Drake Tower [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 24,897,000
Initial Cost to Company, Land and Improvements	1,353,000
Initial Cost to Company, Buildings and Improvements	38,104,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	9,436,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,353,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	47,540,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	48,893,000
Accumulated Depreciation at December 31, 2017	$ 16,287,000
Date of Construction/Acquisition	Dec. 31, 1998
Apartments [Member] | Easthaven at the Village [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 23,775,000
Initial Cost to Company, Land and Improvements	7,919,000
Initial Cost to Company, Buildings and Improvements	39,768,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	8,331,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	8,113,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	47,905,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	56,018,000
Accumulated Depreciation at December 31, 2017	$ 24,034,000
Date of Construction/Acquisition	Dec. 31, 1994
Apartments [Member] | Hamel Mill Lofts [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 47,859,000
Initial Cost to Company, Land and Improvements	3,974,000
Initial Cost to Company, Buildings and Improvements	72,902,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	3,685,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	3,416,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	77,145,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	80,561,000
Accumulated Depreciation at December 31, 2017	$ 15,898,000
Date of Construction/Acquisition	Dec. 31, 2008
Apartments [Member] | Heritage [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	7,433,000
Initial Cost to Company, Buildings and Improvements	42,202,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	10,106,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	7,505,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	52,236,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	59,741,000
Accumulated Depreciation at December 31, 2017	$ 20,226,000
Date of Construction/Acquisition	Dec. 31, 2002
Apartments [Member] | Hummingbird Pointe Apartments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	330,000
Initial Cost to Company, Buildings and Improvements	5,059,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	18,434,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,355,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	22,468,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	23,823,000
Accumulated Depreciation at December 31, 2017	$ 12,012,000
Date of Construction/Acquisition	Dec. 31, 1972
Apartments [Member] | Independence Place I [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 3,852,000
Initial Cost to Company, Land and Improvements	210,000
Initial Cost to Company, Buildings and Improvements	6,671,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,609,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	240,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	8,250,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	8,490,000
Accumulated Depreciation at December 31, 2017	$ 4,867,000
Date of Construction/Acquisition	Dec. 31, 1973
Apartments [Member] | Independence Place II [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 3,334,000
Initial Cost to Company, Land and Improvements	498,000
Initial Cost to Company, Buildings and Improvements	3,931,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	5,446,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	774,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	9,101,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	9,875,000
Accumulated Depreciation at December 31, 2017	$ 3,239,000
Date of Construction/Acquisition	Dec. 31, 2003
Apartments [Member] | KBL [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 15,604,000
Initial Cost to Company, Land and Improvements	716,000
Initial Cost to Company, Buildings and Improvements	23,645,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	5,349,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	719,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	28,991,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	29,710,000
Accumulated Depreciation at December 31, 2017	$ 18,939,000
Date of Construction/Acquisition	Dec. 31, 1990
Apartments [Member] | Knolls [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 31,187,000
Initial Cost to Company, Land and Improvements	53,000
Initial Cost to Company, Buildings and Improvements	23,759,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	826,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	54,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	24,584,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	24,638,000
Accumulated Depreciation at December 31, 2017	$ 13,429,000
Date of Construction/Acquisition	Dec. 31, 1995
Apartments [Member] | Lofts 23 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 5,636,000
Initial Cost to Company, Land and Improvements	221,000
Initial Cost to Company, Buildings and Improvements	17,026,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	372,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	330,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	17,289,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	17,619,000
Accumulated Depreciation at December 31, 2017	$ 5,843,000
Date of Construction/Acquisition	Dec. 31, 2005
Apartments [Member] | Lofts at 1835 Arch [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 36,751,000
Initial Cost to Company, Land and Improvements	2,076,000
Initial Cost to Company, Buildings and Improvements	27,430,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	13,236,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	2,082,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	40,660,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	42,742,000
Accumulated Depreciation at December 31, 2017	$ 13,786,000
Date of Construction/Acquisition	Dec. 31, 2001
Apartments [Member] | Lucky Strike Lofts [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 16,759,000
Initial Cost to Company, Land and Improvements	1,105,000
Initial Cost to Company, Buildings and Improvements	34,095,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,244,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,107,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	35,337,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	36,444,000
Accumulated Depreciation at December 31, 2017	$ 8,520,000
Date of Construction/Acquisition	Dec. 31, 2008
Apartments [Member] | Mercantile Place on Main [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 33,977,000
Initial Cost to Company, Land and Improvements	8,876,000
Initial Cost to Company, Buildings and Improvements	75,478,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	9,037,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	8,805,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	84,586,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	93,391,000
Accumulated Depreciation at December 31, 2017	$ 21,163,000
Date of Construction/Acquisition	Dec. 31, 2008
Apartments [Member] | Metro 417 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 44,699,000
Initial Cost to Company, Land and Improvements	8,545,000
Initial Cost to Company, Buildings and Improvements	67,326,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	5,873,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	8,551,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	73,193,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	81,744,000
Accumulated Depreciation at December 31, 2017	$ 19,893,000
Date of Construction/Acquisition	Dec. 31, 2005
Apartments [Member] | Midtown Towers [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 11,699,000
Initial Cost to Company, Land and Improvements	1,215,000
Initial Cost to Company, Buildings and Improvements	11,091,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	14,934,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,316,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	25,924,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	27,240,000
Accumulated Depreciation at December 31, 2017	$ 12,769,000
Date of Construction/Acquisition	Dec. 31, 1969
Apartments [Member] | Museum Towers [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 28,728,000
Initial Cost to Company, Land and Improvements	3,474,000
Initial Cost to Company, Buildings and Improvements	18,158,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	5,239,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,331,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	25,540,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	26,871,000
Accumulated Depreciation at December 31, 2017	$ 10,630,000
Date of Construction/Acquisition	Dec. 31, 1997
Apartments [Member] | North Church Towers and Gardens [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	789,000
Initial Cost to Company, Buildings and Improvements	4,037,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	3,917,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	887,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	7,856,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	8,743,000
Accumulated Depreciation at December 31, 2017	$ 2,783,000
Date of Construction/Acquisition	Dec. 31, 2009
Apartments [Member] | One Franklintown [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 54,839,000
Initial Cost to Company, Land and Improvements	1,658,000
Initial Cost to Company, Buildings and Improvements	31,489,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	11,471,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,854,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	42,764,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	44,618,000
Accumulated Depreciation at December 31, 2017	$ 23,070,000
Date of Construction/Acquisition	Dec. 31, 1988
Apartments [Member] | Pavilion [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 47,361,000
Initial Cost to Company, Land and Improvements	5,250,000
Initial Cost to Company, Buildings and Improvements	29,505,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	18,713,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	5,251,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	48,217,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	53,468,000
Accumulated Depreciation at December 31, 2017	$ 16,981,000
Date of Construction/Acquisition	Dec. 31, 1992
Apartments [Member] | Presidio Landmark [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 41,950,000
Initial Cost to Company, Land and Improvements	2,060,000
Initial Cost to Company, Buildings and Improvements	92,687,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	5,272,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	2,068,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	97,951,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	100,019,000
Accumulated Depreciation at December 31, 2017	$ 20,393,000
Date of Construction/Acquisition	Dec. 31, 2010
Apartments [Member] | Queenswood [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 27,924,000
Initial Cost to Company, Land and Improvements	321,000
Initial Cost to Company, Buildings and Improvements	39,243,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,666,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	327,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	40,903,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	41,230,000
Accumulated Depreciation at December 31, 2017	$ 20,600,000
Date of Construction/Acquisition	Dec. 31, 1990
Apartments [Member] | River Lofts at Ashton Mill [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	2,885,000
Initial Cost to Company, Buildings and Improvements	33,844,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	12,811,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	3,250,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	46,290,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	49,540,000
Accumulated Depreciation at December 31, 2017	$ 13,752,000
Date of Construction/Acquisition	Dec. 31, 2005
Apartments [Member] | Sky55 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 68,031,000
Initial Cost to Company, Land and Improvements	3,965,000
Initial Cost to Company, Buildings and Improvements	80,930,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	4,469,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	4,016,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	85,348,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	89,364,000
Accumulated Depreciation at December 31, 2017	$ 26,162,000
Date of Construction/Acquisition	Dec. 31, 2006
Apartments [Member] | Stratford Crossing [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	2,813,000
Initial Cost to Company, Buildings and Improvements	27,357,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	585,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	2,826,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	27,929,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	30,755,000
Accumulated Depreciation at December 31, 2017	$ 3,288,000
Date of Construction/Acquisition	Dec. 31, 2007
Apartments [Member] | The Aster Town Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 8,284,000
Initial Cost to Company, Land and Improvements	487,000
Initial Cost to Company, Buildings and Improvements	9,901,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	367,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	494,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	10,261,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	10,755,000
Accumulated Depreciation at December 31, 2017	$ 2,100,000
Date of Construction/Acquisition	Dec. 31, 2012
Apartments [Member] | The Continental [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 35,271,000
Initial Cost to Company, Land and Improvements	1,586,000
Initial Cost to Company, Buildings and Improvements	48,455,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	(1,526,000)
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,586,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	46,929,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	48,515,000
Accumulated Depreciation at December 31, 2017	$ 8,543,000
Date of Construction/Acquisition	Dec. 31, 2013
Apartments [Member] | The Met [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 38,639,000
Initial Cost to Company, Land and Improvements	4,420,000
Initial Cost to Company, Buildings and Improvements	36,557,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	11,042,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	4,501,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	47,518,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	52,019,000
Accumulated Depreciation at December 31, 2017	$ 26,460,000
Date of Construction/Acquisition	Dec. 31, 1989
Apartments [Member] | The Uptown [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 163,851,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	138,710,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	2,249,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	963,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	139,996,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	140,959,000
Accumulated Depreciation at December 31, 2017	$ 18,052,000
Date of Construction/Acquisition	Dec. 31, 2013
Apartments [Member] | The Wilson [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	2,217,000
Initial Cost to Company, Buildings and Improvements	16,565,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	4,455,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,937,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	21,300,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	23,237,000
Accumulated Depreciation at December 31, 2017	$ 5,662,000
Date of Construction/Acquisition	Dec. 31, 2007
Apartments [Member] | Foundry Lofts [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 46,627,000
Initial Cost to Company, Land and Improvements	2,086,000
Initial Cost to Company, Buildings and Improvements	52,806,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	7,847,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	2,096,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	60,643,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	62,739,000
Accumulated Depreciation at December 31, 2017	$ 9,469,000
Date of Construction/Acquisition	Dec. 31, 2011
Apartments [Member] | Twelve12 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 64,768,000
Initial Cost to Company, Land and Improvements	5,444,000
Initial Cost to Company, Buildings and Improvements	106,509,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	3,489,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	5,479,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	109,963,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	115,442,000
Accumulated Depreciation at December 31, 2017	$ 11,570,000
Date of Construction/Acquisition	Dec. 31, 2014
Apartments [Member] | Town Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 35,183,000
Initial Cost to Company, Land and Improvements	3,436,000
Initial Cost to Company, Buildings and Improvements	63,073,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	5,517,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	3,356,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	68,670,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	72,026,000
Accumulated Depreciation at December 31, 2017	$ 23,636,000
Date of Construction/Acquisition	Dec. 31, 2004
Apartments [Member] | Winchester Lofts [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 21,776,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	45,650,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	387,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	4,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	46,033,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	46,037,000
Accumulated Depreciation at December 31, 2017	$ 5,574,000
Date of Construction/Acquisition	Dec. 31, 2014
Land Inventory [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	57,296,000
Initial Cost to Company, Buildings and Improvements	0
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	57,296,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Total	57,296,000
Accumulated Depreciation at December 31, 2017	0
Land Inventory [Member] | Stapleton [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	55,501,000
Initial Cost to Company, Buildings and Improvements	0
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	55,501,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Total	55,501,000
Accumulated Depreciation at December 31, 2017	0
Land Inventory [Member] | Commercial Outlots [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	1,795,000
Initial Cost to Company, Buildings and Improvements	0
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	1,795,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Total	1,795,000
Accumulated Depreciation at December 31, 2017	0
Corporate and Other Equipment [Member] | Corporate Office [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	10,626,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	13,188,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	23,814,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	23,814,000
Accumulated Depreciation at December 31, 2017	10,503,000
Recently-Opened Properties/Redevelopment [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	524,410,000
Initial Cost to Company, Land and Improvements	99,749,000
Initial Cost to Company, Buildings and Improvements	806,558,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	84,544,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	103,804,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	887,047,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	990,851,000
Accumulated Depreciation at December 31, 2017	41,276,000
Recently-Opened Properties/Redevelopment [Member] | 1812 Ashland Ave [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	33,342,000
Initial Cost to Company, Land and Improvements	7,628,000
Initial Cost to Company, Buildings and Improvements	42,574,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,585,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	7,628,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	44,159,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	51,787,000
Accumulated Depreciation at December 31, 2017	$ 2,383,000
Date of Construction/Acquisition	Dec. 31, 2016
Recently-Opened Properties/Redevelopment [Member] | The Bridge at Cornell Tech [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 79,659,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	69,481,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	69,481,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	69,481,000
Accumulated Depreciation at December 31, 2017	$ 780,000
Date of Construction/Acquisition	Dec. 31, 2017
Recently-Opened Properties/Redevelopment [Member] | 461 Dean Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	19,307,000
Initial Cost to Company, Buildings and Improvements	109,208,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	31,969,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	22,584,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	137,900,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	160,484,000
Accumulated Depreciation at December 31, 2017	$ 6,988,000
Date of Construction/Acquisition	Dec. 31, 2016
Recently-Opened Properties/Redevelopment [Member] | Axis [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 63,956,000
Initial Cost to Company, Land and Improvements	14,848,000
Initial Cost to Company, Buildings and Improvements	62,018,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	14,848,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	62,018,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	76,866,000
Accumulated Depreciation at December 31, 2017	$ 781,000
Date of Construction/Acquisition	Dec. 31, 2017
Recently-Opened Properties/Redevelopment [Member] | Blossom Plaza [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 4,790,000
Initial Cost to Company, Land and Improvements	3,237,000
Initial Cost to Company, Buildings and Improvements	81,432,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	146,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	3,261,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	81,554,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	84,815,000
Accumulated Depreciation at December 31, 2017	$ 4,648,000
Date of Construction/Acquisition	Dec. 31, 2016
Recently-Opened Properties/Redevelopment [Member] | Eliot on 4th [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 62,449,000
Initial Cost to Company, Land and Improvements	8,439,000
Initial Cost to Company, Buildings and Improvements	110,347,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	8,954,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	109,832,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	118,786,000
Accumulated Depreciation at December 31, 2017	$ 2,779,000
Date of Construction/Acquisition	Dec. 31, 2017
Recently-Opened Properties/Redevelopment [Member] | Kapolei Lofts [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 91,470,000
Initial Cost to Company, Land and Improvements	34,051,000
Initial Cost to Company, Buildings and Improvements	110,288,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	1,018,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	34,060,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	111,297,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	145,357,000
Accumulated Depreciation at December 31, 2017	$ 10,554,000
Date of Construction/Acquisition	Dec. 31, 2015
Recently-Opened Properties/Redevelopment [Member] | Mint Town Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 48,066,000
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	30,709,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	30,709,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	30,709,000
Accumulated Depreciation at December 31, 2017	$ 282,000
Date of Construction/Acquisition	Dec. 31, 2017
Recently-Opened Properties/Redevelopment [Member] | NorthxNorthwest [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 64,317,000
Initial Cost to Company, Land and Improvements	2,722,000
Initial Cost to Company, Buildings and Improvements	65,977,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	45,970,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	2,952,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	111,717,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	114,669,000
Accumulated Depreciation at December 31, 2017	$ 3,685,000
Date of Construction/Acquisition	Dec. 31, 2016
Recently-Opened Properties/Redevelopment [Member] | The Yards - Arris [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 76,361,000
Initial Cost to Company, Land and Improvements	9,191,000
Initial Cost to Company, Buildings and Improvements	111,825,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	3,856,000
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	9,191,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	115,681,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	124,872,000
Accumulated Depreciation at December 31, 2017	$ 7,751,000
Date of Construction/Acquisition	Dec. 31, 2016
Recently-Opened Properties/Redevelopment [Member] | The Yards - Marina [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	3,044,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	3,044,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	3,044,000
Accumulated Depreciation at December 31, 2017	$ 544,000
Date of Construction/Acquisition	Dec. 31, 2016
Recently-Opened Properties/Redevelopment [Member] | The Yards - District Winery [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	326,000
Initial Cost to Company, Buildings and Improvements	9,655,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	326,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	9,655,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	9,981,000
Accumulated Depreciation at December 31, 2017	$ 101,000
Date of Construction/Acquisition	Dec. 31, 2017
Construction Projects [Member] | The Bridge at Cornell Tech [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	$ 0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	79,976,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	79,976,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	79,976,000
Accumulated Depreciation at December 31, 2017	0
Construction Projects [Member] | Axis [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	12,281,000
Initial Cost to Company, Buildings and Improvements	51,425,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	12,281,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	51,425,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	63,706,000
Accumulated Depreciation at December 31, 2017	0
Construction Projects [Member] | Mint Town Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	619,000
Initial Cost to Company, Buildings and Improvements	51,674,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	619,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	51,674,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	52,293,000
Accumulated Depreciation at December 31, 2017	0
Construction Projects [Member] | NorthxNorthwest [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	13,315,000
Initial Cost to Company, Land and Improvements	11,377,000
Initial Cost to Company, Buildings and Improvements	31,483,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	11,377,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	31,483,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	42,860,000
Accumulated Depreciation at December 31, 2017	0
Construction Projects [Member] | Ardan [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	30,808,000
Initial Cost to Company, Land and Improvements	10,877,000
Initial Cost to Company, Buildings and Improvements	82,141,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	10,877,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	82,141,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	93,018,000
Accumulated Depreciation at December 31, 2017	0
Construction Projects [Member] | Aster Conservatory Green North [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	4,298,000
Initial Cost to Company, Buildings and Improvements	1,413,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	4,298,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	1,413,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	5,711,000
Accumulated Depreciation at December 31, 2017	0
Development Projects [Member] | Miscellaneous Investments [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	5,065,000
Initial Cost to Company, Land and Improvements	881,000
Initial Cost to Company, Buildings and Improvements	8,247,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	881,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	8,247,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	9,128,000
Accumulated Depreciation at December 31, 2017	0
Development Projects [Member] | The Science + Technology Park at Johns Hopkins [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	5,386,000
Initial Cost to Company, Buildings and Improvements	16,483,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	5,386,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	16,483,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	21,869,000
Accumulated Depreciation at December 31, 2017	0
Development Projects [Member] | 5M [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	20,840,000
Initial Cost to Company, Buildings and Improvements	32,802,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	20,840,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	32,802,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	53,642,000
Accumulated Depreciation at December 31, 2017	0
Development Projects [Member] | Pier 70 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	0
Initial Cost to Company, Buildings and Improvements	44,198,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	0
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	44,198,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	44,198,000
Accumulated Depreciation at December 31, 2017	0
Development Projects [Member] | The Yards [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	3,865,000
Initial Cost to Company, Land and Improvements	3,780,000
Initial Cost to Company, Buildings and Improvements	77,714,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	3,780,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	77,714,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	81,494,000
Accumulated Depreciation at December 31, 2017	0
Development Projects [Member] | Waterfront Station [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	0
Initial Cost to Company, Land and Improvements	7,431,000
Initial Cost to Company, Buildings and Improvements	13,226,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	7,431,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	13,226,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	20,657,000
Accumulated Depreciation at December 31, 2017	0
Construction and Development [Member]
Real Estate and Accumulated Depreciation [Line Items]
Amount of Encumbrance at December 31,2017	53,053,000
Initial Cost to Company, Land and Improvements	77,770,000
Initial Cost to Company, Buildings and Improvements	490,782,000
Cost Capitalized Subsequent to Acquisition, Improvements and Carrying Costs	0
Gross Amount at Which Carried at Close of December 31, 2017, Land and Improvements	77,770,000
Gross Amount at Which Carried at Close of December 31, 2017, Buildings and Improvements	490,782,000
Gross Amount at Which Carried at Close of December 31, 2017, Total	568,552,000
Accumulated Depreciation at December 31, 2017	$ 0

Real Estate and Accumulated 151

Real Estate and Accumulated Depreciation (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliations of total real estate carrying value are as follows:
Balance at beginning of period	$ 7,915,565,000	$ 9,613,342,000	$ 8,328,987,000
Additions during period-
Improvements	347,363,000	574,816,000	621,127,000
Acquisitions	0	0	1,254,270,000
Total additions	347,363,000	574,816,000	1,875,397,000
Deductions during period-
Cost of real estate sold or retired	(436,589,000)	(1,256,873,000)	(105,927,000)
Cost of real estate in connection with disposal of partial interests	0	(824,165,000)	0
Other deductions, primarily due to impairments	(45,884,000)	(191,555,000)	(485,115,000)
Total deductions	(482,473,000)	(2,272,593,000)	(591,042,000)
Balance at end of period	7,780,455,000	7,915,565,000	9,613,342,000
Reconciliations of accumulated depreciation are as follows:
Balance at beginning of period	1,442,006,000	1,734,382,000	1,555,965,000
Additions during period - Charged to profit or loss	215,391,000	207,297,000	241,654,000
Net other additions (deductions) during period - Acquisitions, retirements, sales or disposals	(173,234,000)	(499,673,000)	(63,237,000)
Balance at end of period	$ 1,484,163,000	$ 1,442,006,000	$ 1,734,382,000

Real Estate and Accumulated 152

Real Estate and Accumulated Depreciation (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Real Estate and Accumulated Depreciation (Textual) [Abstract]
Aggregate cost for federal income tax purposes	$ 5,381,339
Minimum [Member] | Building and Improvements [Member]
Real Estate and Accumulated Depreciation (Textual) [Abstract]
Estimated useful life of building and improvements	30 years
Minimum [Member] | Equipment and Fixtures [Member]
Real Estate and Accumulated Depreciation (Textual) [Abstract]
Estimated useful life of building and improvements	5 years
Maximum [Member] | Building and Improvements [Member]
Real Estate and Accumulated Depreciation (Textual) [Abstract]
Estimated useful life of building and improvements	50 years
Maximum [Member] | Equipment and Fixtures [Member]
Real Estate and Accumulated Depreciation (Textual) [Abstract]
Estimated useful life of building and improvements	15 years

Mortgage Loan on Real Estate (D

Mortgage Loan on Real Estate (Details)	12 Months Ended
	Dec. 31, 2017USD ($)
Mortgage Loans on Real Estate [Line Items]
Prior Lien (1)	$ 482,000,000
Face Amount of Mortgage	129,535,000
Carrying Amount of Mortgage (2)	129,535,000
Principal Amount of Loan Subject to Delinquent Principal or Interest	$ 0
First Mortgage [Member] | Shops at Northfield Stapleton [Member]
Mortgage Loans on Real Estate [Line Items]
Interest Rate	4.25%
Final Maturity Date	Apr. 30, 2019
Periodic Payment Terms	Interest only
Prior Lien (1)	$ 0
Face Amount of Mortgage	36,935,000
Carrying Amount of Mortgage (2)	36,935,000
Principal Amount of Loan Subject to Delinquent Principal or Interest	$ 0
Second Mortgage [Member] | Barclays Center Arena [Member]
Mortgage Loans on Real Estate [Line Items]
Interest Rate	4.50%
Final Maturity Date	Jan. 31, 2019
Periodic Payment Terms	Interest only
Prior Lien (1)	$ 482,000,000
Face Amount of Mortgage	92,600,000
Carrying Amount of Mortgage (2)	92,600,000
Principal Amount of Loan Subject to Delinquent Principal or Interest	$ 0

Mortgage Loan on Real Estate154

Mortgage Loan on Real Estate (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Mortgage Loan on Real Estate [Abstract]
Balance at beginning of period	$ 92,600,000	$ 0	$ 0
New mortgage loan	36,935,000	92,600,000	0
Deductions during period	0	0	0
Balance at end of period	$ 129,535,000	$ 92,600,000	$ 0