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