Summary of Significant Accounting Policies (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Basic
Income from continuing operations	$ 10,038	$ 7,137
Net loss attributable to non-controlling interest	795	901
Preferred dividend of Series D Preferred Shares	(2,787)	(925)
Amount allocated to restricted shares	(2)
Income from continuing operations applicable to Common Shares	8,044	7,113
Income from discontinued operations	2,913	215
Net income attributable to Common Shares	10,957	7,328
Basic Weighted-Average Common Shares	33,027	33,052
Income from continuing operations	$ 0.24	$ 0.22
Income (loss) from discontinued operations	$ 0.09
Net income attributable to Winthrop Realty Trust	$ 0.33	$ 0.22
Diluted
Income from continuing operations	10,038	7,137
Net loss attributable to non-controlling interest	795	901
Preferred dividend of Series D Preferred Shares	(2,787)	(925)
Amount allocated to restricted shares	(2)
Income from continuing operations applicable to Common Shares	8,044	7,113
Income from discontinued operations	2,913	215
Net income attributable to Common Shares	$ 10,957	$ 7,328
Basic Weighted-Average Common Shares	33,027	33,052
Stock options (1)	2
Restricted shares (2)	51
Diluted Weighted-Average Common Shares	33,080	33,052
Income from continuing operations	$ 0.24	$ 0.22
Income (loss) from discontinued operations	$ 0.09
Net income attributable to Winthrop Realty Trust	$ 0.33	$ 0.22