Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data	Sep. 30, 2011	Dec. 31, 2010
Investments in real estate, at cost
Allowances on accounts receivable	$ 594	$ 262
LIABILITIES
Series B-1 Cumulative Convertible Redeemable Preferred Shares, liquidation preference	$ 25	$ 25
Series B-1 Cumulative Convertible Redeemable Preferred Shares, shares authorized	852,000	852,000
Series B-1 Cumulative Convertible Redeemable Preferred Shares, shares outstanding	852,000	852,000
NON-CONTROLLING REDEEMABLE PREFERRED INTEREST
Series C Cumulative Convertible Redeemable Preferred Shares, liquidation preference	$ 25	$ 25
Series C Cumulative Convertible Redeemable Preferred Shares, shares authorized	144,000	144,000
Series C Cumulative Convertible Redeemable Preferred Shares, shares outstanding	144,000	144,000
Winthrop Realty Trust Shareholders' Equity:
Common shares, par value	$ 1	$ 1
Common shares authorized	unlimited	unlimited
Common shares, shares issued	32,958,778	27,030,186
Common shares, shares outstanding	32,958,778	27,030,186