Reportable Segments (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating Properties
Rents and reimbursements	$ 15,179	$ 11,793
Real estate taxes	(946)	(1,192)
Equity in (loss) income of equity investments	7,869	424
Depreciation and amortization expense	(5,174)	(3,537)
Interest expense	(6,032)	(3,724)
Loan Assets
Interest income	70	101
Loan discount accretion	716	2,833
General and administrative expense	(847)	(883)
Provision for loss on loans receivable	0
REIT Securities
Interest and dividends	5,320	5,518
(Loss) gain on sale of securities carried at fair value	(102)	26
Corporate Income (Expense)
Related party fees	2,266	2,027
Income from continuing operations before non-controlling interest	10,038	7,137
Non-controlling interest	(795)	(901)
Income from discontinued operations	2,913	215
Operating Segments [Member]
Operating Properties
Rents and reimbursements	15,179	11,793
Operating expenses	(4,930)	(4,331)
Real estate taxes	(946)	(1,192)
Operating income	12,413	6,027
Depreciation and amortization expense	(5,174)	(3,537)
Interest expense	(3,625)	(3,098)
Operating properties net income (loss)	3,614	(608)
Operating Segments [Member] | Fenway-Wateridge [Member]
Operating Properties
Equity in earnings of preferred equity investment	202
Equity in (loss) income of equity investments	36
Operating Segments [Member] | Sealy Northwest Atlanta [Member]
Operating Properties
Equity in (loss) income of equity investments	(146)	(56)
Operating Segments [Member] | Sealy Newmarket [Member]
Operating Properties
Equity in (loss) income of equity investments		(722)
Operating Segments [Member] | Marc Realty [Member]
Operating Properties
Equity in (loss) income of equity investments	(60)	(347)
Operating Segments [Member] | WRT Elad [Member]
Operating Properties
Equity in (loss) income of equity investments	443	543
Operating Segments [Member] | Vintage [Member]
Operating Properties
Equity in (loss) income of equity investments	1,921	339
Operating Segments [Member] | 701 Seventh Avenue [Member]
Operating Properties
Equity in (loss) income of equity investments	697
Operating Segments [Member] | Mentor [Member]
Operating Properties
Equity in (loss) income of equity investments	17
Loan Assets [Member]
Operating Properties
Operating income	10,131	6,063
Interest expense	(580)	(334)
Operating properties net income (loss)	9,537	5,724
Loan Assets
Interest income	4,454	2,399
Loan discount accretion	716	2,833
Unrealized gain on loan securities carried at fair value		164
General and administrative expense	(14)	(5)
Loan Assets [Member] | Sealy ROIC Riverside [Member]
Operating Properties
Equity in (loss) income of equity investments		234
Loan Assets [Member] | ROIC Lakeside Eagle [Member]
Operating Properties
Equity in (loss) income of equity investments	(13)	(12)
Loan Assets [Member] | Concord Debt Holdings [Member]
Operating Properties
Equity in (loss) income of equity investments	35	296
Loan Assets [Member] | CDH CDO LLC [Member]
Operating Properties
Equity in (loss) income of equity investments	150	394
Loan Assets [Member] | Concord Debt Holdings (1) [Member]
Operating Properties
Equity in earnings of preferred equity investment	14
Loan Assets [Member] | CDH CDO (1) [Member]
Operating Properties
Equity in earnings of preferred equity investment	480
Loan Assets [Member] | WRT-Stamford [Member]
Operating Properties
Equity in (loss) income of equity investments	221	89
Loan Assets [Member] | SoCal Office Loan Portfolio [Member]
Operating Properties
Equity in (loss) income of equity investments		(345)
Loan Assets [Member] | RE CDO Management [Member]
Operating Properties
Equity in (loss) income of equity investments	3,770	11
Loan Assets [Member] | 10 Metrotech [Member]
Operating Properties
Equity in (loss) income of equity investments	304
REIT Securities [Member]
Operating Properties
Operating properties net income (loss)	1,766	5,244
Loan Assets
Unrealized gain on loan securities carried at fair value	1,718	4,932
REIT Securities
Interest and dividends	150	286
(Loss) gain on sale of securities carried at fair value	(102)	26
Net income from segments before corporate income (expense)	14,917	10,360
Corporate Income (Expense)
Net Income Attributable to Winthrop Realty Trust	14,917	10,360
Reconciliations to GAAP Net Income [Member]
Operating Properties
Interest expense	1,827	292
Loan Assets
Interest income	70	101
General and administrative expense	833	878
REIT Securities
Net income from segments before corporate income (expense)	13,746	8,253
Corporate Income (Expense)
Related party fees	(2,266)	(2,027)
Transaction costs	(6)	(121)
State and local taxes	(17)	(6)
Income from continuing operations before non-controlling interest	10,038	7,137
Non-controlling interest	795	901
Income from continuing operations	10,833	8,038
Income from discontinued operations	2,913	215
Net Income Attributable to Winthrop Realty Trust	$ 13,746	$ 8,253