Reportable Segments (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Operating Properties
Real estate taxes	$ 1,268	$ 1,079	$ 3,481	$ 3,360
Equity in income of equity investments	12,644	2,820	13,654	4,340
Depreciation and amortization expense	4,842	3,111	12,872	9,751
Interest expense	4,430	3,480	11,602	11,926
Impairment loss on investment in real estate		(3,000)		(3,000)
Gain on extinguishment of debt		8,514		8,514
Gain on sale of equity investment	165	207	397	207
Loan Assets
Interest	242	472	433	1,007
Discount accretion	425	2,374	5,984	11,167
General and administrative expense	3,098	2,691	9,088	7,816
Interest expense	4,430	3,480	11,602	11,926
REIT Securities
Interest and dividends	3,722	5,503	15,018	20,269
Gain on sale of securities carried at fair value			41	131
Corporate Income (Expense)
Interest income	242	472	433	1,007
Interest expense	4,430	3,480	11,602	11,926
General and administrative	3,098	2,691	9,088	7,816
Income from continuing operations before non-controlling interest	16,235	10,262	26,343	21,481
Non-controlling interest	939	318	(435)	851
Income from discontinued operations attributable to Winthrop Realty Trust	(188)	(98)	(59)	142
Capital Expenditures
Operating properties	1,896	2,141	7,972	5,856
Operating Segments [Member]
Operating Properties
Rents and reimbursements	13,335	10,370	38,225	31,696
Operating expenses	(3,624)	(3,272)	(11,535)	(10,856)
Real estate taxes	(1,268)	(1,079)	(3,481)	(3,360)
Operating income	9,177	5,178	23,417	19,463
Depreciation and amortization expense	(4,842)	(3,111)	(12,872)	(9,751)
Interest expense	(3,140)	(2,824)	(9,272)	(9,809)
Impairment loss on investment in real estate		(3,000)		(3,000)
Gain on extinguishment of debt		8,514		8,514
Gain on sale of equity investment	165	207	397	207
Operating properties net income	1,360	4,964	1,670	1,824
Loan Assets
Operating income	9,177	5,178	23,417	19,463
Interest expense	(3,140)	(2,824)	(9,272)	(9,809)
REIT Securities
REIT Securities net income (loss)	1,360	4,964	1,670	1,824
Corporate Income (Expense)
Interest expense	(3,140)	(2,824)	(9,272)	(9,809)
Operating Segments [Member] | Sealy Northwest Atlanta [Member]
Operating Properties
Equity in income of equity investments	(109)	(119)	(273)	4,422
Operating Segments [Member] | Sealy Airpark Nashville [Member]
Operating Properties
Equity in income of equity investments		(275)		(728)
Operating Segments [Member] | Sealy New Market [Member]
Operating Properties
Equity in income of equity investments	(704)	(672)	(2,171)	(1,816)
Operating Segments [Member] | Sealy Equity Investment [Member]
Operating Properties
Impairment loss				(3,800)
Operating Segments [Member] | Marc Realty [Member]
Operating Properties
Equity in income of equity investments	212	(199)	(132)	(319)
Operating Segments [Member] | W R T Elad One South Street Lender L P [Member]
Operating Properties
Equity in income of equity investments	(57)		458
Operating Segments [Member] | Vintage [Member]
Operating Properties
Equity in income of equity investments	1,392	424	2,326	424
Loan Assets [Member]
Operating Properties
Operating income	15,691	9,260	28,007	29,034
Interest expense	(336)	(184)	(1,004)	(525)
Operating properties net income	15,340	9,033	26,963	28,451
Loan Assets
Interest	2,985	3,043	8,130	8,440
Discount accretion	425	2,374	5,984	11,167
Unrealized gain (loss) on loan securities carried at fair value	371	(75)	447	2,772
Operating income	15,691	9,260	28,007	29,034
General and administrative expense	(15)	(43)	(40)	(58)
Interest expense	(336)	(184)	(1,004)	(525)
REIT Securities
Unrealized gain (loss) on loan securities carried at fair value	371	(75)	447	2,772
REIT Securities net income (loss)	15,340	9,033	26,963	28,451
Corporate Income (Expense)
Interest income	2,985	3,043	8,130	8,440
Interest expense	(336)	(184)	(1,004)	(525)
General and administrative	(15)	(43)	(40)	(58)
Loan Assets [Member] | L W Sofi [Member]
Operating Properties
Equity in income of equity investments		855		1,117
Loan Assets [Member] | Marc Realty [Member]
Loan Assets
Equity in earnings of preferred equity investment		85		253
Loan Assets [Member] | 450 W 14th Street [Member]
Loan Assets
Equity in earnings of preferred equity investment		172		245
Loan Assets [Member] | Sealy ROIC Riverside [Member]
Operating Properties
Equity in income of equity investments	238	234	706	702
Loan Assets [Member] | ROIC Lakeside Eagle [Member]
Operating Properties
Equity in income of equity investments	(16)		(32)	666
Loan Assets [Member] | 46th Street Gotham [Member]
Operating Properties
Equity in income of equity investments				621
Loan Assets [Member] | Lex-Win Concord [Member]
Loan Assets
Equity in earnings of preferred equity investment		49		307
Loan Assets [Member] | Concord Debt Holdings [Member]
Operating Properties
Equity in income of equity investments	35	2,500	386	2,721
Loan Assets [Member] | C D H C D O L L C [Member]
Operating Properties
Equity in income of equity investments	136		670
Loan Assets [Member] | Concord Debt Holdings (1) [Member]
Operating Properties
Equity in income of equity investments	2		30
Loan Assets [Member] | CDH CDO (1) [Member]
Operating Properties
Equity in income of equity investments	855		1,333
Loan Assets [Member] | WRT-Stamford [Member]
Operating Properties
Equity in income of equity investments	232		548
Loan Assets [Member] | Socal Office Portfolio Loan [Member]
Operating Properties
Equity in income of equity investments	10,348		9,710
Loan Assets [Member] | RE CDO Management [Member]
Operating Properties
Equity in income of equity investments	18	23	46	23
Loan Assets [Member] | Loss of 10 Metrotech [Member]
Operating Properties
Equity in income of equity investments	50		31
Loan Assets [Member] | Income of Mentor [Member]
Operating Properties
Equity in income of equity investments	12		18
REIT Securities [Member]
Operating Properties
Operating properties net income	3,425	(875)	8,199	(5)
Loan Assets
Unrealized gain (loss) on loan securities carried at fair value	3,113	(961)	7,254	(798)
REIT Securities
Interest and dividends	312	86	904	662
Gain on sale of securities carried at fair value			41	131
Unrealized gain (loss) on loan securities carried at fair value	3,113	(961)	7,254	(798)
REIT Securities net income (loss)	3,425	(875)	8,199	(5)
Net income from segments before corporate income (expense)	20,125	13,122	36,832	30,270
Corporate Income (Expense)
Net Income attributable to Winthrop Realty Trust	20,125	13,122	36,832	30,270
Reconciliations to GAAP Net Income [Member]
Operating Properties
Interest expense	(954)	(472)	(1,326)	(1,592)
Loan Assets
Interest	242	472	433	1,007
General and administrative expense	(3,083)	(2,648)	(9,048)	(7,758)
Interest expense	(954)	(472)	(1,326)	(1,592)
REIT Securities
Net income from segments before corporate income (expense)	15,108	9,846	26,719	20,722
Corporate Income (Expense)
Interest income	242	472	433	1,007
Interest expense	(954)	(472)	(1,326)	(1,592)
General and administrative	(3,083)	(2,648)	(9,048)	(7,758)
Transaction costs	(30)	(201)	(335)	(358)
State and local taxes	(65)	(11)	(213)	(88)
Income from continuing operations before non-controlling interest	16,235	10,262	26,343	21,481
Non-controlling interest	(939)	(318)	435	(851)
Income from continuing operations attributable to Winthrop Realty Trust	15,296	9,944	26,778	20,630
Income from discontinued operations attributable to Winthrop Realty Trust	(188)	(98)	(59)	142
Net Income attributable to Winthrop Realty Trust	$ 15,108	$ 9,846	$ 26,719	$ 20,722