XML 70 R56.htm IDEA: XBRL DOCUMENT v3.10.0.1

Stock Option Plan - Additional Information (Detail)											12 Months Ended
	May 11, 2018 USD ($) person $ / shares shares	May 05, 2017 USD ($) person $ / shares shares	May 06, 2016 USD ($) person $ / shares shares	May 08, 2015 USD ($) person $ / shares shares	May 09, 2014 USD ($) person $ / shares shares	May 10, 2013 USD ($) person $ / shares shares	May 04, 2012 USD ($) person $ / shares shares	May 13, 2011 USD ($) person $ / shares shares	May 07, 2010 USD ($) person $ / shares shares	Apr. 24, 2009 USD ($) person $ / shares shares	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 $ / shares	Dec. 31, 2016 $ / shares	Dec. 31, 2004 shares	Dec. 31, 1993 shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares											$ 49.46	$ 59.41	$ 57.74
Fair value stock option grant | $											$ 13,060,000
the 1993 Plan | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Authorized shares for a grant (in shares)															400,000
Amended 2004 Plan | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Authorized shares for a grant (in shares)														2,000,000
Amended 2004 Plan | Stock options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Authorized shares for a grant (in shares)														200,000
2009 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares										$ 32.68
Fair value stock option grant | $										$ 222,950
2009 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person										13
2009 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)										0
2009 Options | Stock options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)										32,500
2010 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares									$ 38.76
Fair value stock option grant | $									$ 287,950
2010 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person									13
2010 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)									0
2010 Options | Stock options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)									32,500
2011 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares								$ 41.82
Fair value stock option grant | $								$ 1,600,000
2011 Options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person								15
Fair value stock option grant | $								$ 1,300,000
Options vested								25.00%
2011 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person								13
Fair value stock option grant | $								$ 297,375
2011 Options | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)								195,000
2011 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option vesting period								4 years
2011 Options | Incentive stock option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)								65,300
2011 Options | Nonqualified stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)								129,700
2012 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares							$ 39.29
Fair value stock option grant | $							$ 1,700,000
2012 Options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person							15
Fair value stock option grant | $							$ 1,400,000
Options vested							25.00%
2012 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person							14
Fair value stock option grant | $							$ 257,250
2012 Options | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)							277,500
2012 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option vesting period							4 years
2012 Options | Incentive stock option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)							26,157
2012 Options | Nonqualified stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)							251,343
2013 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person						15
Exercise price of options (in usd per share) | $ / shares						$ 44.42
Fair value stock option grant | $						$ 1,500,000
2013 Options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Fair value stock option grant | $						$ 1,200,000
Options vested						25.00%
2013 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person						14
Fair value stock option grant | $						$ 278,250
2013 Options | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)						237,500
2013 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option vesting period						4 years
2013 Options | Incentive stock option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)						35,592
2013 Options | Nonqualified stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)						201,908
2014 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares					$ 47.03
Fair value stock option grant | $					$ 1,300,000
2014 Options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person					18
Fair value stock option grant | $					$ 1,200,000
Options vested					25.00%
2014 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person					12
Fair value stock option grant | $					$ 109,500
2014 Options | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)					200,000
2014 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option vesting period					4 years
2014 Options | Incentive stock option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)					29,300
2014 Options | Nonqualified stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)					170,700
2015 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares				$ 51.07
Fair value stock option grant | $				$ 1,570,000
2015 Options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person				19
Fair value stock option grant | $				$ 1,440,000
Options vested				25.00%
2015 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person				14
Fair value stock option grant | $				$ 125,300
2015 Options | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)				225,000
2015 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option vesting period				4 years
2015 Options | Incentive stock option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)				33,690
2015 Options | Nonqualified stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)				191,310
2016 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares			$ 57.74
Fair value stock option grant | $			$ 1,200,000
2016 Options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person			19
Fair value stock option grant | $			$ 1,000,000
Options vested			25.00%
2016 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person			13
Fair value stock option grant | $			$ 151,100
2016 Options | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)			226,500
2016 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option vesting period			4 years
2016 Options | Incentive stock option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)			24,248
2016 Options | Nonqualified stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)			202,252
2017 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares		$ 59.41
Fair value stock option grant | $		$ 1,400,000
2017 Options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person		20
Fair value stock option grant | $		$ 1,200,000
Options vested		25.00%
2017 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person		11
Fair value stock option grant | $		$ 165,600
2017 Options | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)		232,500
2017 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option vesting period		4 years
2017 Options | Incentive stock option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)		21,492
2017 Options | Nonqualified stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)		211,008
2018 Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price of options (in usd per share) | $ / shares	$ 49.46
Fair value stock option grant | $	$ 1,400,000
2018 Options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person	22
Fair value stock option grant | $	$ 1,200,000
Options vested	25.00%
2018 Options | Director
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of individuals granted options | person	11
Fair value stock option grant | $	$ 169,400
2018 Options | Stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)	245,000
2018 Options | Stock options | Officer
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option vesting period	4 years
2018 Options | Incentive stock option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)	25,914
2018 Options | Nonqualified stock options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options granted to purchase stocks (in shares)	219,086

X

- Definition

Share Based Compensation Arrangement By Share Based Payment Award Number Of Employees Granted Awards

+ References

No definition available.

+ Details

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

X

- Definition

Share based Compensation Arrangement by Share based Payment Award, Options, Grants in Period, Fair Value

+ References

No definition available.

+ Details

Name:	bfs_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodFairValue
Namespace Prefix:	bfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Share Based Compensation Arrangement By Share Based Payment Award Options Vested Percentage

+ References

No definition available.

+ Details

Name:	bfs_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedPercentage
Namespace Prefix:	bfs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

+ Details

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

X

- Definition

Net number of share options (or share units) granted during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

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

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_StockOptionPlanNineteenNinetyThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_AmendedStockOptionPlanTwentyZeroFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_TitleOfIndividualAxis=us-gaap_DirectorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_StockOptionPlanTwentyZeroNineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_TitleOfIndividualAxis=us-gaap_OfficerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_StockOptionPlanTwentyTenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_StockOptionPlanTwentyElevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AwardTypeAxis=bfs_IncentiveStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_AwardTypeAxis=bfs_NonqualifiedStockOptionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_StockOptionPlanTwentyTwelveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_StockOptionPlan2013Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_StockOptionPlanTwentyFourteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_StockOptionPlanTwentyFifteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_A2016OptionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_A2017OptionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=bfs_A2018OptionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: