XML 59 R45.htm IDEA: XBRL DOCUMENT v3.10.0.1

Noncontrolling Interests - Holders of Convertible Limited Partnership Units in Operating Partnership - Additional Information (Detail) - Noncontrolling Interests	12 Months Ended
	Dec. 31, 2018 shares	Dec. 31, 2017 shares	Dec. 31, 2016 shares
Noncontrolling Interest [Line Items]
Limited partnership units (in shares)	7,825,980
Limited partnership units, conversion ratio	1
Outstanding stock percent that should be acquired for rights to be exercised	39.90%
Limited partnership units convertible to shares of common stock, eligible for conversion (in shares)	920,000
Fully converted partnership units and diluted weighted average shares outstanding (in shares)	30,156,100	29,510,900	28,989,900
Saul Holdings Limited Partnership
Noncontrolling Interest [Line Items]
Percentage of ownership interest of noncontrolling interest	25.70%

X

- Definition

Limited Partners' Capital Account, Convertible Units, Conversion Ratio

+ References

No definition available.

+ Details

Name:	bfs_LimitedPartnersCapitalAccountConvertibleUnitsConversionRatio
Namespace Prefix:	bfs_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Limited Partners' Capital Account, Convertible Units, Eligible for Conversion

+ References

No definition available.

+ Details

Name:	bfs_LimitedPartnersCapitalAccountConvertibleUnitsEligibleForConversion
Namespace Prefix:	bfs_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Minimum Outstanding Stock Percentage That Should be Acquired for Rights Issued to Become Exercisable

+ References

No definition available.

+ Details

Name:	bfs_MinimumOutstandingStockPercentageThatShouldBeAcquiredForRightsIssuedToBecomeExercisable
Namespace Prefix:	bfs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Partners' Capital Account, Units, Converted and Weighted Average Shares Outstanding, Diluted

+ References

No definition available.

+ Details

Name:	bfs_PartnersCapitalAccountUnitsConvertedAndWeightedAverageSharesOutstandingDiluted
Namespace Prefix:	bfs_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of limited partner units outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70434-108055

+ Details

Name:	us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

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

X

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_NoncontrollingInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_OwnershipAxis=bfs_SaulHoldingsLimitedPartnershipMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: