Reportable Segments (Details 1) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011
Operating Properties
Real estate taxes	$ 1,017,000		$ 1,087,000		$ 2,271,000	$ 2,342,000
Income of equity investments	586,000		2,875,000		1,010,000	1,520,000
Depreciation and amortization	4,479,000		3,312,000		8,198,000	6,793,000
Interest expense	3,512,000		3,963,000		7,301,000	8,576,000
Gain on sale of equity investment	232,000				232,000
Loan Assets
Interest	90,000		443,000		192,000	536,000
Discount accretion	2,726,000		2,289,000		5,559,000	8,793,000
General and administrative expense	3,264,000		2,758,000		6,295,000	5,282,000
Interest expense	3,512,000		3,963,000		7,301,000	8,576,000
REIT Securities
Interest and dividends	5,778,000		5,094,000		11,296,000	14,766,000
Gain on sale of securities carried at fair value	15,000		7,000		41,000	131,000
Corporate Income (Expense)
Interest income	90,000		443,000		192,000	536,000
Interest expense	3,512,000		3,963,000		7,301,000	8,576,000
General and administrative	3,264,000		2,758,000		6,295,000	5,282,000
Income from continuing operations	2,885,000		3,967,000		10,240,000	11,322,000
Non-controlling interest	(473,000)		329,000		(1,374,000)	533,000
Income from discontinued operations attributable to Winthrop Realty Trust			90,000		(3,000)	137,000
Capital Expenditures
Operating properties		4,831,000		896,000	6,076,000	3,715,000
Lex-Win Concord [Member]
Loan Assets
Equity in earnings of preferred equity investment			258,000			258,000
Concord Debt Holdings (1) [Member]
Loan Assets
Equity in earnings of preferred equity investment	28,000				28,000
CDH CDO (1) [Member]
Loan Assets
Equity in earnings of preferred equity investment	478,000				478,000
Operating Segments [Member]
Operating Properties
Rents and reimbursements	13,257,000		11,234,000		25,797,000	22,220,000
Operating expenses	(3,779,000)		(3,987,000)		(8,331,000)	(8,032,000)
Real estate taxes	(1,017,000)		(1,087,000)		(2,271,000)	(2,342,000)
Operating income		8,410,000		10,229,000	14,669,000	14,670,000
Depreciation and amortization		(4,479,000)		(3,312,000)	(8,198,000)	(6,793,000)
Interest expense		(3,098,000)		(3,296,000)	(6,261,000)	(7,115,000)
Gain on sale of equity investment		232,000			232,000
Operating properties net income (loss)		833,000		(179,000)	442,000	(3,038,000)
Loan Assets
Operating income		8,410,000		10,229,000	14,669,000	14,670,000
Interest expense		(3,098,000)		(3,296,000)	(6,261,000)	(7,115,000)
REIT Securities
Operating income (loss)		833,000		(179,000)	442,000	(3,038,000)
Corporate Income (Expense)
Interest expense		(3,098,000)		(3,296,000)	(6,261,000)	(7,115,000)
Operating Segments [Member] | Sealy Northwest Atlanta [Member]
Operating Properties
Income of equity investments	(108,000)		5,133,000		(164,000)	4,541,000
Operating Segments [Member] | Sealy Airpark Nashville [Member]
Operating Properties
Income of equity investments			(256,000)			(453,000)
Operating Segments [Member] | Sealy New Market [Member]
Operating Properties
Income of equity investments	(745,000)		(633,000)		(1,467,000)	(1,144,000)
Operating Segments [Member] | Sealy Equity Investment [Member]
Operating Properties
Impairment loss on Sealy equity investment			(3,800,000)			(3,800,000)
Operating Segments [Member] | Marc Realty [Member]
Operating Properties
Income of equity investments	3,000		(175,000)		(344,000)	(120,000)
Operating Segments [Member] | WRT-Elad One South Street Lender LP[Member]
Operating Properties
Income of equity investments	(28,000)				515,000
Operating Segments [Member] | Vintage [Member]
Operating Properties
Income of equity investments	595,000				934,000
Loan Assets [Member]
Operating Properties
Operating income		6,253,000		7,774,000	12,316,000	19,774,000
Interest expense		(334,000)		(184,000)	(668,000)	(341,000)
Operating properties net income (loss)		5,899,000		7,579,000	11,623,000	19,418,000
Loan Assets
Interest		2,746,000		2,687,000	5,145,000	5,397,000
Discount accretion		2,726,000		2,289,000	5,559,000	8,793,000
Unrealized (loss) gain on loan securities carried at fair value		(88,000)	34,000		76,000	2,847,000
Operating income		6,253,000		7,774,000	12,316,000	19,774,000
General and administrative expense		20,000		(11,000)	25,000	(15,000)
Interest expense		(334,000)		(184,000)	(668,000)	(341,000)
REIT Securities
Unrealized (loss) gain on loan securities carried at fair value		(88,000)	34,000		76,000	2,847,000
Operating income (loss)		5,899,000		7,579,000	11,623,000	19,418,000
Corporate Income (Expense)
Interest income		2,746,000		2,687,000	5,145,000	5,397,000
Interest expense		(334,000)		(184,000)	(668,000)	(341,000)
General and administrative		20,000		(11,000)	25,000	(15,000)
Loan Assets [Member] | L W Sofi [Member]
Loan Assets
Equity in earnings of preferred equity investment			262,000			262,000
Loan Assets [Member] | Marc Realty [Member]
Loan Assets
Equity in earnings of preferred equity investment				85,000		168,000
Loan Assets [Member] | 450 W 14th Street [Member]
Loan Assets
Equity in earnings of preferred equity investment			73,000			73,000
Loan Assets [Member] | Sealy ROIC Riverside [Member]
Operating Properties
Income of equity investments		234,000		234,000
Loan Assets
Equity in earnings of preferred equity investment					468,000	468,000
Loan Assets [Member] | ROIC Lakeside Eagle [Member]
Operating Properties
Income of equity investments		(4,000)		922,000
Loan Assets
Equity in earnings of preferred equity investment					(16,000)	666,000
Loan Assets [Member] | 46th Street Gotham [Member]
Operating Properties
Income of equity investments				709,000
Loan Assets
Equity in earnings of preferred equity investment						621,000
Loan Assets [Member] | Concord Debt Holdings [Member]
Operating Properties
Income of equity investments		55,000		221,000
Loan Assets
Equity in earnings of preferred equity investment					351,000	221,000
Loan Assets [Member] | CDH CDO [Member]
Operating Properties
Income of equity investments		140,000
Loan Assets
Equity in earnings of preferred equity investment					534,000
Loan Assets [Member] | WRT-Stamford [Member]
Operating Properties
Income of equity investments		227,000
Loan Assets
Equity in earnings of preferred equity investment					316,000
Loan Assets [Member] | Socal Office Portfolio Loan [Member]
Operating Properties
Income of equity investments		(293,000)
Loan Assets
Equity in earnings of preferred equity investment					(638,000)
Loan Assets [Member] | RE CDO Management [Member]
Operating Properties
Income of equity investments		17,000
Loan Assets
Equity in earnings of preferred equity investment					28,000
Loan Assets [Member] | Loss of 10 Metrotech [Member]
Operating Properties
Income of equity investments	(19,000)				(19,000)
Loan Assets [Member] | Income of Mentor [Member]
Operating Properties
Income of equity investments	6,000				6,000
REIT Securities [Member]
Operating Properties
Operating properties net income (loss)		(470,000)		(598,000)	4,774,000	870,000
Loan Assets
Unrealized (loss) gain on loan securities carried at fair value		(791,000)		(723,000)	4,141,000	163,000
REIT Securities
Interest and dividends		306,000		118,000	592,000	576,000
Gain on sale of securities carried at fair value		15,000		7,000	41,000	131,000
Unrealized (loss) gain on loan securities carried at fair value		(791,000)		(723,000)	4,141,000	163,000
Operating income (loss)		(470,000)		(598,000)	4,774,000	870,000
Net Income		6,262,000		6,802,000	16,839,000	17,250,000
Corporate Income (Expense)
Net income attributable to Winthrop Realty Trust		6,262,000		6,802,000	16,839,000	17,250,000
Reconciliations to GAAP Net Income [Member]
Operating Properties
Interest expense		(80,000)		(483,000)	(372,000)	(1,120,000)
Loan Assets
Interest		90,000		443,000	192,000	536,000
General and administrative expense		(3,244,000)		(2,747,000)	(6,270,000)	(5,267,000)
Interest expense		(80,000)		(483,000)	(372,000)	(1,120,000)
REIT Securities
Net Income		3,358,000		3,728,000	11,611,000	10,926,000
Corporate Income (Expense)
Interest income		90,000		443,000	192,000	536,000
Interest expense		(80,000)		(483,000)	(372,000)	(1,120,000)
General and administrative		(3,244,000)		(2,747,000)	(6,270,000)	(5,267,000)
State and local taxes		(143,000)		(48,000)	(149,000)	(77,000)
Income from continuing operations		2,885,000		3,967,000	10,240,000	11,322,000
Non-controlling interest		473,000		(329,000)	1,374,000	(533,000)
Income (Loss) from Continuing Operations Attributable to Parent, Total		3,358,000		3,638,000	11,614,000	10,789,000
Income from discontinued operations attributable to Winthrop Realty Trust				90,000	(3,000)	137,000
Net income attributable to Winthrop Realty Trust		$ 3,358,000		$ 3,728,000	$ 11,611,000	$ 10,926,000