Consolidated Statement of Equity (USD $) Share data in Thousands	Total	Series D Preferred Shares of Beneficial Interest [Member]	Series D 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 Distributions in Excess of Net Income [Member] Series D Preferred Shares of Beneficial Interest [Member]	Accumulated Other Comprehensive Income (loss) [Member]	Non-Controlling Interests [Member]
Beginning balance at Dec. 31, 2014	$ 509,663,000		$ 120,500,000	$ 35,809,000	$ 647,121,000	$ (322,432,000)		$ (124,000)	$ 28,789,000
Beginning balance, shares at Dec. 31, 2014			4,820	36,401
Net income attributable to Winthrop Realty Trust	641,000					641,000
Net loss attributable to non-controlling interests	(1,443,000)								(1,443,000)
Distributions to non-controlling interests	(20,000)								(20,000)
Contributions from non-controlling interests	149,000								149,000
Increase in non-controlling interest due to consolidation of property	16,391,000								16,391,000
Decrease in non-controlling interest due to property sale	(3,764,000)								(3,764,000)
Dividends declared on Common Shares of Beneficial Interest ($0.1625 per share)	(5,820,000)					(5,820,000)
Dividends declared on Series D Preferred Shares ($0.578125 per share)	(2,787,000)	(2,787,000)					(2,787,000)
Dividends declared on Restricted Shares	(96,000)					(96,000)
Change in unrealized loss on interest rate derivatives	(145,000)							(145,000)
Stock issued pursuant to Dividend Reinvestment Plan	91,000			8,000	83,000
Stock issued pursuant to Dividend Reinvestment Plan, shares				8
Amortization of Restricted Shares	414,000				414,000
Ending balance at Mar. 31, 2015	$ 513,274,000		$ 120,500,000	$ 35,817,000	$ 647,618,000	$ (330,494,000)		$ (269,000)	$ 40,102,000
Ending balance, shares at Mar. 31, 2015			4,820	36,409