XML 77 R63.htm IDEA: XBRL DOCUMENT
v3.20.4

Impact of COVID-19 - Narrative (Details) | 3 Months Ended | 14 Months Ended
--- | --- | ---
Dec. 31, 2020 | Feb. 22, 2022
Subsequent Event [Line Items] |  |
Rent deferral period | 3 months |
Subsequent Event |  |
Subsequent Event [Line Items] |  |
Deferred Rent, Percent Due |  | 0
Contractual Base Rent, Operating Expense And Real Estate Recoveries Collected | Revenue |  |
Subsequent Event [Line Items] |  |
Percentage of total revenue | 94.00% |
Operating lease income subject to deferral agreements | Outstanding Billings | Revenue |  |
Subsequent Event [Line Items] |  |
Percentage of total revenue | 0.50% |
Operating lease income subject to deferral agreements | April, May, June 2020 unpaid balance as percent of total unpaid balance | Revenue |  |
Subsequent Event [Line Items] |  |
Percentage of total revenue | 9.00% |
Retail Real Estate | Contractual Base Rent, Operating Expense And Real Estate Recoveries Collected | Revenue |  |
Subsequent Event [Line Items] |  |
Percentage of total revenue | 94.00% |
Office Real Estate | Contractual Base Rent, Operating Expense And Real Estate Recoveries Collected | Revenue |  |
Subsequent Event [Line Items] |  |
Percentage of total revenue | 93.00% |
Residential Real Estate | Contractual Base Rent, Operating Expense And Real Estate Recoveries Collected | Revenue |  |
Subsequent Event [Line Items] |  |
Percentage of total revenue | 100.00% |

X
- Definition Deferred Rent, Percent Due + References No definition available. + Details
Name: | bfs_DeferredRentPercentDue
Namespace Prefix: | bfs_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Real Estate, Rent Deferral Period + References No definition available. + Details
Name: | bfs_RealEstateRentDeferralPeriod
Namespace Prefix: | bfs_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 42 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13531-108611 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13537-108611 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=bfs_ContractualBaseRentOperatingExpenseAndRealEstateRecoveriesCollectedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=bfs_OperatingLeaseIncomeSubjectToDeferralAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=bfs_OutstandingBillingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=bfs_AprilMayJune2020UnpaidBalanceAsPercentOfTotalUnpaidBalanceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=bfs_RetailRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=bfs_OfficeRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=us-gaap_ResidentialRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |