Consolidated Statement of Equity (USD $) In Thousands, except Share data	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		1,600,000	33,041,000
Net income attributable to Winthrop Realty Trust	11,611				11,611
Net loss attributable to non-controlling interests	(1,374)						(1,374)
Distributions to non-controlling interests	(270)						(270)
Contributions from non-controlling interests	3,975						3,975
Purchase of non-controlling interests	(6,250)			(5,695)			(555)
Dividends paid or accrued on Common Shares of Beneficial Interest ($0.325 per share in 2013, 2012 respectively)	(10,744)				(10,744)
Dividends paid or accrued on Series D Preferred Shares ($1.15625 per share)	(3,712)				(3,712)
Net proceeds from Series D Preferred Share offering	77,715	80,500		(2,785)
Net proceeds from Series D Preferred Share offering, shares		3,220,000
Change in unrealized gain on interest rate derivatives	(57)					(57)
Stock issued pursuant to dividend reinvestment plan	268		25	243
Stock issued pursuant to dividend reinvestment plan, shares			25,000
Ending balance at Jun. 30, 2012	479,998	120,500	33,066	617,862	(314,091)	(149)	22,810
Ending balance, shares at Jun. 30, 2012		4,820,000	33,066,000
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		4,820,000	33,019,000
Net income attributable to Winthrop Realty Trust	22,120				22,120
Net loss attributable to non-controlling interests	(1,424)						(1,424)
Contributions from non-controlling interests	535						535
Purchase of non-controlling interests	(150)			103			(253)
Dividends paid or accrued on Common Shares of Beneficial Interest ($0.325 per share in 2013, 2012 respectively)	(10,736)				(10,736)
Dividends paid or accrued on Series D Preferred Shares ($1.15625 per share)	(5,573)				(5,573)
Dividends paid or accrued on restricted shares	(114)				(114)
Change in unrealized gain on interest rate derivatives	130					130
Stock issued pursuant to dividend reinvestment plan	234		20	214
Stock issued pursuant to dividend reinvestment plan, shares			20,000
Issuance of restricted shares, Value
Issuance of restricted shares	600,000		600,000
Amortization of restricted shares	211			211
Ending balance at Jun. 30, 2013	$ 474,497	$ 120,500	$ 33,039	$ 618,954	$ (311,688)	$ 80	$ 13,612
Ending balance, shares at Jun. 30, 2013		4,820,000	33,639,000