Reportable Segments (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Properties
Rents and reimbursements	$ 51,375,000	$ 42,789,000	$ 36,274,000
Real estate taxes	4,765,000	4,427,000	2,412,000
Equity (loss) income	14,678,000	(12,712,000)	(2,007,000)
Depreciation and amortization expense	17,666,000	13,234,000	9,628,000
Interest expense	17,658,000	15,759,000	15,114,000
Impairment loss on investment in real estate	(2,562,000)	(7,600,000)
(Loss) gain on extinguishment of debt, net	(121,000)	9,258,000
Gain on consolidation of property		818,000
Loan Assets
Accretion of loan discount	8,333,000	13,401,000	8,782,000
Gain on sale of securities carried at fair value	614,000		469,000
General and administrative expense	3,561,000	3,558,000	3,402,000
Provision for loss on loans receivable	0	0	0
REIT Securities
Realized gain on sale of securities carried at fair value	41,000	123,000	558,000
Corporate Income (Expense)
State and local taxes	234,000	379,000	134,000
Income from continuing operations before non-controlling interest	24,451,000	11,092,000	19,106,000
Loss attributable to non-controlling interest	(247,000)	814,000	888,000
Operating Segments [Member]
Operating Properties
Rents and reimbursements	51,375,000	42,789,000	36,274,000
Operating expenses	(15,666,000)	(14,387,000)	(7,758,000)
Real estate taxes	(4,765,000)	(4,427,000)	(2,412,000)
Operating income	33,119,000	23,444,000	24,870,000
Depreciation and amortization expense	(17,666,000)	(13,234,000)	(9,628,000)
Interest expense	(13,011,000)	(12,815,000)	(12,932,000)
Impairment loss on investment in real estate	(2,562,000)	(7,600,000)
(Loss) gain on extinguishment of debt, net	(121,000)	9,358,000
Gain on sale of equity investments	397,000	207,000
Settlement income		5,868,000
Gain on consolidation of property		818,000
Operating properties net income (loss)	156,000	(15,012,000)	2,310,000
Operating Segments [Member] | Marc Realty [Member]
Operating Properties
Equity (loss) income	(132,000)	(982,000)	1,776,000
Impairment loss		(15,764,000)
Operating Segments [Member] | Sealy Northwest Atlanta [Member]
Operating Properties
Equity (loss) income	(388,000)	4,308,000	(710,000)
Operating Segments [Member] | Sealy Airpark Nashville [Member]
Operating Properties
Equity (loss) income		(1,034,000)	(1,107,000)
Operating Segments [Member] | Sealy Newmarket [Member]
Operating Properties
Equity (loss) income	(3,811,000)	(2,936,000)	(1,193,000)
Operating Segments [Member] | Sealy Equity Investment [Member]
Operating Properties
Impairment loss		(5,294,000)
Operating Segments [Member] | Vintage [Member]
Operating Properties
Equity (loss) income	4,603,000	113,000
Operating Segments [Member] | WRT Elad [Member]
Operating Properties
Equity (loss) income	903,000
Loan Assets [Member]
Operating Properties
Operating income	33,401,000	36,220,000	19,518,000
Interest expense	(1,494,000)	(850,000)
Operating properties net income (loss)	31,786,000	35,295,000	19,218,000
Loan Assets
Interest	11,736,000	11,073,000	5,691,000
Accretion of loan discount	8,333,000	13,401,000	8,782,000
Gain on sale of securities carried at fair value	614,000		469,000
Unrealized gain on loan securities carried at fair value	447,000	2,738,000	5,011,000
General and administrative expense	(121,000)	(75,000)	(300,000)
Impairment loss on preferred equity investments
Provision for loss on loans receivable
Loan Assets [Member] | Marc Realty [Member]
Loan Assets
Equity in earnings (loss) of preferred equity investment		338,000	338,000
Loan Assets [Member] | Lex-Win Concord [Member]
Operating Properties
Impairment loss
Loan Assets
Equity in earnings (loss) of preferred equity investment		258,000
Loan Assets [Member] | Sealy ROIC Riverside [Member]
Operating Properties
Equity (loss) income	706,000	936,000	473,000
Loan Assets [Member] | ROIC Lakeside Eagle [Member]
Operating Properties
Equity (loss) income	(42,000)	664,000
Loan Assets [Member] | 46th Street Gotham [Member]
Operating Properties
Equity (loss) income		621,000
Loan Assets [Member] | Sofitel [Member]
Operating Properties
Equity (loss) income		2,177,000
Loan Assets [Member] | Concord Debt Holdings [Member]
Operating Properties
Equity (loss) income	422,000	3,216,000
Loan Assets [Member] | CDH CDO LLC [Member]
Operating Properties
Equity (loss) income	1,715,000	480,000
Loan Assets [Member] | Concord Debt Holdings (1) [Member]
Loan Assets
Equity in earnings (loss) of preferred equity investment	(456,000)
Loan Assets [Member] | CDH CDO (1) [Member]
Loan Assets
Equity in earnings (loss) of preferred equity investment	(997,000)
Loan Assets [Member] | WRT-Stamford LLC [Member]
Operating Properties
Equity (loss) income	769,000
Loan Assets [Member] | 10 Metrotech [Member]
Operating Properties
Equity (loss) income	335,000
Loan Assets [Member] | Mentor [Member]
Operating Properties
Equity (loss) income	46,000
Loan Assets [Member] | PSW NYC [Member]
Operating Properties
Equity (loss) income			(1,246,000)
Loan Assets [Member] | SoCal Office Portfolio Loan LLC [Member]
Operating Properties
Equity (loss) income	9,706,000	272,000
Loan Assets [Member] | RE CDO Management LLC [Member]
Operating Properties
Equity (loss) income	67,000	46,000
REIT Securities [Member]
Operating Properties
Operating properties net income (loss)	8,011,000	3,895,000	8,273,000
Loan Assets
Unrealized gain on loan securities carried at fair value	6,916,000	2,788,000	5,060,000
REIT Securities
Dividends	1,054,000	984,000	2,655,000
Realized gain on sale of securities carried at fair value	41,000	123,000	558,000
Net Income	39,953,000	24,178,000	29,801,000
Reconciliations to GAAP Net Income [Member]
Operating Properties
Interest expense	(3,153,000)	(2,094,000)	(2,182,000)
Loan Assets
Interest	699,000	1,179,000	139,000
General and administrative expense	(12,393,000)	(11,173,000)	(8,198,000)
Corporate Income (Expense)
Transaction costs	(421,000)	(519,000)	(321,000)
State and local taxes	(234,000)	(379,000)	(133,000)
Income from continuing operations before non-controlling interest	24,451,000	11,092,000	19,106,000
Loss attributable to non-controlling interest	247,000	(814,000)	(888,000)
Income from continuing operations attributable to Winthrop Realty Trust	24,698,000	10,278,000	18,218,000
Reconciliations to GAAP Net Income [Member] | Series B-1 [Member]
REIT Securities
Realized gain on sale of securities carried at fair value		$ (100,000)