Consolidated Statements of Capital - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Increase (Decrease) in Partners' Capital [Roll Forward]
Net Income, excluding amounts attributable to redeemable noncontrolling Interests	$ 62,675	$ 46,990	$ 115,668	$ 95,921
Other comprehensive income (loss) - change in fair value of interest rate swaps, excluding portion attributable to redeemable noncontrolling interests	2,025	(938)	5,597	2,406
Contributions from noncontrolling interests		6,554		6,554
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Other comprehensive income (loss) - change in fair value of interest rate swaps, excluding portion attributable to redeemable noncontrolling interests	2,025	(938)	5,597	2,406
Federal Realty OP LP
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	2,714,577	2,604,960	2,663,148	2,548,747
Net Income, excluding amounts attributable to redeemable noncontrolling Interests	62,675	46,990	115,668	95,921
Other comprehensive income (loss) - change in fair value of interest rate swaps, excluding portion attributable to redeemable noncontrolling interests	2,025	(938)	5,597	2,406
Distributions declared to common unit holders	(84,977)	(82,417)	(169,173)	(164,788)
Distributions declared to preferred unit holders	(2,008)	(2,011)	(4,018)	(4,021)
Distributions declared to noncontrolling interests in consolidated partnerships, excluding amounts attributable to redeemable noncontrolling interests	(866)	(943)	(2,625)	(1,727)
Common units issued as a result of common stock issued by Parent Company, net of issuance costs	176,703	(81)	259,452	87,133
Common units issued under dividend reinvestment plan	509	474	1,011	1,019
Share-based compensation expense, net of forfeitures	3,500	3,358	7,679	7,507
Common units withheld for employee taxes	(37)	(8)	(4,638)	(2,813)
Conversion of preferred units	0		0
Contributions from noncontrolling interests		6,554		6,554
Partners' Capital, Other	4,326		4,326
Ending balance	2,876,427	2,575,839	2,876,427	2,575,839
Federal Realty OP LP | downREIT OP units
Increase (Decrease) in Partners' Capital [Roll Forward]
Conversion and redemption of downREIT OP units	0	(99)	0	(99)
Federal Realty OP LP | Preferred Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	154,963	154,963	154,963	154,963
Net Income, excluding amounts attributable to redeemable noncontrolling Interests	2,008	2,011	4,018	4,021
Distributions declared to preferred unit holders	(2,008)	(2,011)	(4,018)	(4,021)
Conversion of preferred units (units)	175		175
Conversion of preferred units	(175)		(175)
Ending balance	154,788	154,963	154,788	154,963
Federal Realty OP LP | Common Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	2,477,270	2,368,315	2,427,686	2,314,838
Net Income, excluding amounts attributable to redeemable noncontrolling Interests	59,668	44,193	109,642	90,419
Distributions declared to common unit holders	(84,977)	(82,417)	(169,173)	(164,788)
Common units issued as a result of common stock issued by Parent Company, net of issuance costs	176,703	(81)	259,452	87,133
Common units issued under dividend reinvestment plan	509	474	1,011	1,019
Share-based compensation expense, net of forfeitures	3,500	3,358	7,679	7,507
Common units withheld for employee taxes	(37)	(8)	(4,638)	(2,813)
Conversion of preferred units	175		175
Partners' Capital, Other	4,326		4,326
Ending balance	2,637,545	2,338,364	2,637,545	2,338,364
Federal Realty OP LP | Common Units | downREIT OP units
Increase (Decrease) in Partners' Capital [Roll Forward]
Conversion and redemption of downREIT OP units	408	4,530	1,385	5,049
Federal Realty OP LP | Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	1,525	(2,300)	(2,047)	(5,644)
Other comprehensive income (loss) - change in fair value of interest rate swaps, excluding portion attributable to redeemable noncontrolling interests	2,025	(938)	5,597	2,406
Ending balance	3,550	(3,238)	3,550	(3,238)
Federal Realty OP LP | Total Partner Capital
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	2,633,758	2,520,978	2,580,602	2,464,157
Net Income, excluding amounts attributable to redeemable noncontrolling Interests	61,676	46,204	113,660	94,440
Other comprehensive income (loss) - change in fair value of interest rate swaps, excluding portion attributable to redeemable noncontrolling interests	2,025	(938)	5,597	2,406
Distributions declared to common unit holders	(84,977)	(82,417)	(169,173)	(164,788)
Distributions declared to preferred unit holders	(2,008)	(2,011)	(4,018)	(4,021)
Common units issued as a result of common stock issued by Parent Company, net of issuance costs	176,703	(81)	259,452	87,133
Common units issued under dividend reinvestment plan	509	474	1,011	1,019
Share-based compensation expense, net of forfeitures	3,500	3,358	7,679	7,507
Common units withheld for employee taxes	(37)	(8)	(4,638)	(2,813)
Partners' Capital, Other	4,326		4,326
Ending balance	2,795,883	2,490,089	2,795,883	2,490,089
Federal Realty OP LP | Total Partner Capital | downREIT OP units
Increase (Decrease) in Partners' Capital [Roll Forward]
Conversion and redemption of downREIT OP units	408	4,530	1,385	5,049
Federal Realty OP LP | Noncontrolling Interests in Consolidated Partnerships
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	80,819	83,982	82,546	84,590
Net Income, excluding amounts attributable to redeemable noncontrolling Interests	999	786	2,008	1,481
Distributions declared to noncontrolling interests in consolidated partnerships, excluding amounts attributable to redeemable noncontrolling interests	(866)	(943)	(2,625)	(1,727)
Contributions from noncontrolling interests		6,554		6,554
Ending balance	80,544	85,750	80,544	85,750
Federal Realty OP LP | Noncontrolling Interests in Consolidated Partnerships | downREIT OP units
Increase (Decrease) in Partners' Capital [Roll Forward]
Conversion and redemption of downREIT OP units	$ (408)	$ (4,629)	$ (1,385)	$ (5,148)