Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Operating real estate, consolidated variable interest entities	$ 1,963,129	$ 2,207,648
Construction-in-progress, consolidated variable interest entities	23,448	18,752
Accumulated depreciation and amortization, consolidated variable interest entities	349,553	389,950
Mortgages payable, consolidated variable interest entities	$ 192,442	$ 335,301
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, authorized	15,000,000	15,000,000
Common shares of beneficial interest, par value	$ 0.01	$ 0.01
Common shares of beneficial interest, shares outstanding	81,204,286	78,603,305
Common shares of beneficial interest, shares issued	81,204,286	78,603,305
Common shares of beneficial interest, shares authorized	100,000,000	100,000,000
Federal Realty OP LP
Operating real estate, consolidated variable interest entities	$ 1,963,129	$ 2,207,648
Construction-in-progress, consolidated variable interest entities	23,448	18,752
Accumulated depreciation and amortization, consolidated variable interest entities	349,553	389,950
Mortgages payable, consolidated variable interest entities	$ 192,442	$ 335,301
Preferred units, issued	398,878	405,896
Preferred units, outstanding	398,878	405,896
Common units, issued	81,204,286	78,603,305
Common units, outstanding	81,204,286	78,603,305
5.0% Series C Cumulative Redeemable Preferred Shares, (stated at liquidation preference $25,000 per share), 6,000 shares issued and outstanding
Preferred shares, percentage	5.00%	5.00%
Preferred shares, liquidation preference	$ 25,000	$ 25,000
Preferred shares, shares outstanding	6,000	6,000
Preferred shares, shares issued	6,000	6,000
5.417% Series 1 Cumulative Convertible Preferred Shares, (stated at liquidation preference $25 per share), 392,878 and 399,896 shares issued and outstanding, respectively
Preferred shares, percentage	5.417%	5.417%
Preferred shares, liquidation preference	$ 25	$ 25
Preferred shares, shares outstanding	392,878	399,896
Preferred shares, shares issued	392,878	399,896