Acquisition and Disposition Activities - Accompanying Unaudited Pro Forma Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	7 Months Ended	12 Months Ended
Jul. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Combinations [Abstract]
Total revenue	$ 57,101	$ 108,333	$ 112,694
Income (loss) from continuing operations	(2,776)	7,666	10,610
Net income attributable to Winthrop Realty Trust	$ 12,480	$ 24,414	$ 17,519
Per common share data - basic	$ 0.16	$ 0.38	$ 0.25
Per common share data - diluted	$ 0.16	$ 0.38	$ 0.25

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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