Savings and Retirement Plans (Details) - 401(K) and Deferred Compensation Plan - USD ($)	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
401(k) Maximum annual contribution per employee	$ 22,500	$ 20,500	$ 19,500
401(k) Employer match	50.00%	50.00%	50.00%
401(k) Employer contribution expense	$ 960,000	$ 869,000	$ 816,000
Deferred compensation liability to participants	$ 22,000,000	$ 18,000,000
Maximum
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
401(k) Maximum of employer match as a percentage of employee eligible earnings	5.00%	5.00%	5.00%

Deferred Compensation Arrangement with Individual, Employer Contribution Per Employee, Matching Percent

No definition available.

Name:	frt_DeferredCompensationArrangementWithIndividualEmployerContributionPerEmployeeMatchingPercent
Namespace Prefix:	frt_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of contributions made by employer into fund established for purposes of making future disbursement to individual in accordance with deferred compensation arrangement.

+ References

No definition available.

+ Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying amount of the liability as of the balance sheet date to an individual under a deferred compensation arrangement. This amount may be the result of periodic accruals made over the period of active employment, or reflect termination benefits resulting contractual terms or a death benefit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 710
-SubTopic 10
-Name Accounting Standards Codification
-Section 30
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483043/710-10-30-1

+ Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum amount the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsByTypeOfDeferredCompensationAxis=us-gaap_DeferredCompensationArrangementWithIndividualByTypeOfCompensationPensionAndOtherPostretirementBenefitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: