Consolidated Statements of Equity (USD $) In Thousands	Total	Preferred Shares of Beneficial Interest [Member]	Common Shares of Beneficial Interest [Member]	Additional Paid-In Capital [Member]	Accumulated Distributions in Excess of Net Income [Member]	Accumulated Other Comprehensive Income (loss) [Member]	Non-Controlling Interests [Member]
Beginning balance at Dec. 31, 2011	$ 408,836	$ 40,000	$ 33,041	$ 626,099	$ (311,246)	$ (92)	$ 21,034
Beginning balance, shares at Dec. 31, 2011		1,600	33,041
Net income attributable to Winthrop Realty Trust	26,719				26,719
Net loss attributable to non-controlling interests	(435)						(435)
Distributions to non-controlling interests	(6,115)						(6,115)
Contributions from non-controlling interests	4,340						4,340
Purchase of non-controlling interests	(6,250)			(5,695)			(555)
Dividends paid or accrued on Common Shares of Beneficial Interest ($0.4875 per share in 2013, 2012 respectively)	(16,119)				(16,119)
Dividends paid or accrued on Series D Preferred Shares ($1.7344 and $1.15625 per share for 2013 and 2012 respectively)	(6,498)				(6,498)
Net proceeds from Series D Preferred Share offering	77,572	80,500		(2,928)
Net proceeds from Series D Preferred Share offering, shares		3,220
Change in unrealized gain/loss on interest rate derivatives	(73)					(73)
Stock issued pursuant to Dividend Reinvestment Plan	397		36	361
Stock issued pursuant to Dividend Reinvestment Plan, shares			36
Ending balance at Sep. 30, 2012	482,374	120,500	33,077	617,837	(307,144)	(165)	18,269
Ending balance, shares at Sep. 30, 2012		4,820	33,077
Beginning balance at Dec. 31, 2012	469,264	120,500	33,019	618,426	(317,385)	(50)	14,754
Beginning balance, shares at Dec. 31, 2012		4,820	33,019
Net income attributable to Winthrop Realty Trust	33,848				33,848
Net loss attributable to non-controlling interests	(2,419)						(2,419)
Distributions to non-controlling interests	(52)						(52)
Contributions from non-controlling interests	861						861
Purchase of non-controlling interests	(150)			103			(253)
Dividends paid or accrued on Common Shares of Beneficial Interest ($0.4875 per share in 2013, 2012 respectively)	(16,553)				(16,553)
Dividends paid or accrued on Series D Preferred Shares ($1.7344 and $1.15625 per share for 2013 and 2012 respectively)	(8,360)				(8,360)
Dividends paid or accrued on restricted shares	(211)				(211)
Change in unrealized gain/loss on interest rate derivatives	(20)					(20)
Stock issued pursuant to Dividend Reinvestment Plan	353		29	324
Stock issued pursuant to Dividend Reinvestment Plan, shares			29
Net proceeds from common shares offering	29,960		2,750	27,210
Net proceeds from common shares offering, shares			2,750
Issuance of restricted shares, Value
Issuance of restricted shares	600		600
Amortization of restricted shares	557			557
Ending balance at Sep. 30, 2013	$ 507,078	$ 120,500	$ 35,798	$ 646,620	$ (308,661)	$ (70)	$ 12,891
Ending balance, shares at Sep. 30, 2013		4,820	36,398