Earnings Per Share And Unit (Schedule Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 159,956	$ 114,655	$ 226,534	$ 172,671
Dividends on preferred shares	(2,008)	(2,008)	(4,016)	(4,016)
Less: Income from operations attributable to noncontrolling interests	(4,040)	(2,673)	(6,850)	(3,953)
Earnings Allocated To Unvested Shares	(520)	(399)	(727)	(663)
Net income available for common shareholders, basic	153,388	109,575	214,941	164,039
Add: Income attributable to downREIT operating partnership units	601	686	1,268	0
Net income available for common shareholders, diluted	$ 154,122	$ 110,261	$ 216,209	$ 164,039
Weighted average number of common shares, Basic	85,969	82,932	85,722	82,768
DownREIT operating partnership units	548	631	578	0
5.417% Series 1 Cumulative Convertible Preferred Units	94	0	0	0
Weighted average number of common shares, Diluted	86,611	83,563	86,300	82,768
Net income available for common shareholders, Basic	$ 1.78	$ 1.32	$ 2.51	$ 1.98
Net income available for common shareholders, Diluted	$ 1.78	$ 1.32	$ 2.51	$ 1.98
Federal Realty OP LP
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 159,956	$ 114,655	$ 226,534	$ 172,671
Distributions on preferred units	(2,008)	(2,008)	(4,016)	(4,016)
Less: Income from operations attributable to noncontrolling interests	(4,040)	(2,673)	(6,850)	(3,953)
Earnings allocated to unvested units	(520)	(399)	(727)	(663)
Net income available for common unit holders, basic	153,388	109,575	214,941	164,039
Add: Income attributable to downREIT operating partnership units	601	686	1,268	0
Net income available for common unit holders, diluted	$ 154,122	$ 110,261	$ 216,209	$ 164,039
Weighted average number of common units, Basic	85,969	82,932	85,722	82,768
DownREIT operating partnership units	548	631	578	0
Weighted average common units outstanding, diluted	86,611	83,563	86,300	82,768
Net income available for common unit holders, Basic	$ 1.78	$ 1.32	$ 2.51	$ 1.98
Net income available for common unit holders, Diluted	$ 1.78	$ 1.32	$ 2.51	$ 1.98
5.417% Series 1 Cumulative Convertible Preferred Shares, (stated at liquidation preference $25 per share), 392,878 shares issued and outstanding
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Add: Dividends on 5.417% Series 1 Cumulative Convertible Preferred Shares	$ 133	$ 0	$ 0	$ 0
Preferred Units | Federal Realty OP LP
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Add: Dividends on 5.417% Series 1 Cumulative Convertible Preferred Units	$ 133	$ 0	$ 0	$ 0
5.417% Series 1 Cumulative Convertible Preferred Units	94	0	0	0