Acquisition and Disposition Activity - Accompanying Unaudited Pro Forma Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended	7 Months Ended	9 Months Ended
Jul. 31, 2014	Sep. 30, 2013	Jul. 31, 2014	Sep. 30, 2013
Business Combinations [Abstract]
Total revenue	$ 8,479	$ 21,245	$ 57,101	$ 64,654
Income (loss) from continuing operations	2,400	10,448	(2,776)	29,879
Net income attributable to Winthrop Realty Trust	$ 2,879	$ 11,129	$ 12,480	$ 33,486
Per common share data - basic	$ 0.05	$ 0.25	$ 0.16	$ 0.76
Per common share data - diluted	$ 0.05	$ 0.25	$ 0.16	$ 0.76

The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect, for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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