Entity Information [Line Items] Entity Information [Line Items] Federal Realty OP LP Federal Realty OP LP [Member] Federal Realty OP LP Depository Shares Depository Shares [Member] Depository Shares [Member] Document Period End Date Document Period End Date Pre-commencement Tender Offer Pre-commencement Tender Offer Class of Stock [Domain] Class of Stock [Domain] Soliciting Material Soliciting Material City Area Code City Area Code Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Central Index Key Entity Central Index Key Entity Address, City or Town Entity Address, City or Town Security Exchange Name Security Exchange Name Title of 12(b) Security Title of 12(b) Security Written Communications Written Communications Common Shares Of Beneficial Interest Common Shares Of Beneficial Interest [Member] Common Shares Of Beneficial Interest [Member] Local Phone Number Local Phone Number Trading Symbol Trading Symbol Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Address, State or Province Entity Address, State or Province Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Cover [Abstract] Cover [Abstract] Entity Emerging Growth Company Entity Emerging Growth Company Entity [Domain] Entity [Domain] Document Type Document Type Amendment Flag Amendment Flag Class of Stock [Axis] Class of Stock [Axis] Entity File Number Entity File Number Legal Entity [Axis] Legal Entity [Axis] Entities [Table] Entities [Table] Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Registrant Name Entity Registrant Name