Business Acquisition, Expenses Reimbursed

No definition available.

Name:	bfs_BusinessAcquisitionExpensesReimbursed
Namespace Prefix:	bfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Lessee, Operating Lease, Incremental Borrowing Rate

+ References

No definition available.

+ Details

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Namespace Prefix:	bfs_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Lessee, Operating Lease, Option To Extend, Number Of Options

+ References

No definition available.

+ Details

Name:	bfs_LesseeOperatingLeaseOptionToExtendNumberOfOptions
Namespace Prefix:	bfs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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-SubTopic 30
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-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Area of land held.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of consideration transferred in asset acquisition. Includes, but is not limited to, cash, liability incurred by acquirer, and equity interest issued by acquirer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 50
-Section 30
-Paragraph 2
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-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=123362884&loc=d3e9212-128498

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The aggregate costs of keeping the property in good condition but that do not appreciably prolong the life or increase the value of the property.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2)
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

+ Details

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- Definition

For an unclassified balance sheet, the accumulated amortization, as of the reporting date, which represents the periodic charge to earnings of initial direct costs which have been deferred and are being allocated over the lease term in proportion to the recognition of rental income.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 25
-Paragraph 10
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-URI http://asc.fasb.org/extlink&oid=123394697&loc=d3e40879-112712

+ Details

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- Definition

This element represents costs incurred by the lessor that are (a) costs to originate a lease incurred in transactions with independent third parties that (i) result directly from and are essential to acquire that lease and (ii) would not have been incurred had that leasing transaction not occurred and (b) certain costs directly related to specified activities performed by the lessor for that lease. Those activities are: evaluating the prospective lessee's financial condition; evaluating and recording guarantees, collateral, and other security arrangements; negotiating lease terms; preparing and processing lease documents; and closing the transaction. This element is net of accumulated amortization.

+ References

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- Definition

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

+ References

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-Publisher FASB
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-Paragraph 1
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Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest expense on finance lease liability.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
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-Section 55
-Paragraph 53
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+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Amount of amortization expense attributable to right-of-use asset from finance lease.

+ References

+ Details

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

- Definition

The charge against earnings in the period to reduce the carrying amount of real property to fair value.

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-Publisher FASB
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+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
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+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Term of lessor's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
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-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
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+ Details

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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 1
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-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3213-108585

+ Details

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Period Type:	duration

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(d))
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+ Details

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- 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

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- Definition

Number of shares of stock issued during the period pursuant to acquisitions.

+ References

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- Details

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- Details

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Real Estate Transactions - Narrative (Details)				9 Months Ended
Real Estate Transactions - Narrative (Details)	Sep. 30, 2021 USD ($) shares	Jun. 29, 2021 USD ($) shares	Nov. 05, 2019 a shares	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Mar. 05, 2021 USD ($) a	Dec. 31, 2020 USD ($)	Jan. 01, 2019 leaseExtensionOption
Real Estate [Line Items]
Assets placed in service	$ 2,266,362,000			$ 2,266,362,000			$ 2,124,796,000
Lease renewal term								5 years
Right-of-use asset	321,900			321,900
Operating lease liability	334,500			334,500
Deferred leasing costs, net	24,638,000			24,638,000			26,872,000
Accumulated amortization deferred leasing cost	$ 47,700,000			47,700,000			$ 44,500,000
Depreciation expense				34,200,000	$ 33,600,000
Repairs and maintenance expense				10,200,000	8,000,000
Impairment of real estate				$ 0
Business acquisition, expenses reimbursed						$ 7,400,000
Operating lease, incremental borrowing rate				5.63%
Finance lease, right-of-use asset, amortization				$ 104,000
Finance lease, interest expense				$ 362,800
Contribution Agreement
Real Estate [Line Items]
Right-of-use asset						19,400,000
Operating lease liability						19,400,000
Number of partnership units issued in transaction (in shares) \| shares			1,416,071
Business acquisition, transaction costs						$ 1,200,000
Leasehold Interest Contributed In Contribution Agreement
Real Estate [Line Items]
Number of partnership units issued in transaction (in shares) \| shares	469,740
Asset acquisition consideration transferred		$ 21,500,000
Payments to acquire businesses, gross		$ 700,000
Leasehold Interest Contributed In Contribution Agreement \| Limited Partner
Real Estate [Line Items]
Number of partnership units issued in transaction (in shares) \| shares		469,740
BF Saul Real Estate Investment Trust \| Contribution Agreement
Real Estate [Line Items]
Area of land \| a			10.3
Minimum
Real Estate [Line Items]
Operating lease term of contract	1 year			1 year
Maximum
Real Estate [Line Items]
Operating lease term of contract	15 years			15 years
Building \| Minimum
Real Estate [Line Items]
Estimated useful life				35 years
Building \| Maximum
Real Estate [Line Items]
Estimated useful life				50 years
Building Improvements \| Maximum
Real Estate [Line Items]
Estimated useful life				20 years
Lease Acquisition Costs
Real Estate [Line Items]
Amortization of intangible assets				$ 3,600,000	$ 4,000,000
The Waycroft and Ashbrook Marketplace
Real Estate [Line Items]
Assets placed in service	$ 8,700,000			$ 8,700,000
Corporate Headquarters
Real Estate [Line Items]
Number of options to extend lease \| leaseExtensionOption								1
Twinbrook Metro Station \| BF Saul Real Estate Investment Trust \| Contribution Agreement
Real Estate [Line Items]
Area of land \| a			6.8			6.8
Twinbrook Metro Station Leasehold Interest \| BF Saul Real Estate Investment Trust \| Contribution Agreement
Real Estate [Line Items]
Area of land \| a			1.3			1.3