Summary Of Significant Accounting Policies (Supplemental Cash Flow Disclosures) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
SUPPLEMENTAL DISCLOSURES:
Total interest costs incurred	$ 114,912us-gaap_InterestCostsIncurred	$ 121,158us-gaap_InterestCostsIncurred	$ 123,441us-gaap_InterestCostsIncurred
Interest capitalized	(20,971)us-gaap_InterestCostsCapitalized	(16,181)us-gaap_InterestCostsCapitalized	(10,105)us-gaap_InterestCostsCapitalized
Interest expense	93,941us-gaap_InterestExpense	104,977us-gaap_InterestExpense	113,336us-gaap_InterestExpense
Cash paid for interest, net of amounts capitalized	100,011us-gaap_InterestPaidNet	120,934us-gaap_InterestPaidNet	114,419us-gaap_InterestPaidNet
Cash paid (refunded) for income taxes	278us-gaap_IncomeTaxesPaidNet	410us-gaap_IncomeTaxesPaidNet	(1,151)us-gaap_IncomeTaxesPaidNet
NON-CASH INVESTING AND FINANCING TRANSACTIONS:
Mortgage loans assumed with acquisition	68,282	0	67,615
DownREIT operating partnership units issued with acquisition	65,348	0	0
Mortgage loans refinanced	64,205frt_Refinanceofmortgageloan	0frt_Refinanceofmortgageloan	0frt_Refinanceofmortgageloan
Repayment of note payable with public funding/related construction-in-progress offset	10,000	0	0
Shares issued under dividend reinvestment plan	$ 1,855	$ 1,779	$ 1,864
Minimum \| Retail and commercial
Operating Leased Assets [Line Items]
Operating lease, term	3 years
Maximum \| Retail and commercial
Operating Leased Assets [Line Items]
Operating lease, term	10 years

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Value of downREIT Operating Partnership Units Issued in Connection with Business Acquisition

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

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