Document and Entity Information Document	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2014	Aug. 04, 2014
Entity Information [Line Items]
Entity Registrant Name	FEDERAL REALTY INVESTMENT TRUST
Entity Central Index Key	0000034903
Current Fiscal Year End Date		--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2014
Document Fiscal Year Focus		2014
Document Fiscal Period Focus	Q2
Amendment Flag	false
Trading Symbol	FRT
Entity Common Stock, Shares Outstanding			67,718,240
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes