XML 88 R72.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Fair Value Of Financial Instruments (Quantitative Information related To The Significant Unobservable Inputs Utilized In Company's Level 3 Recurring Fair Value Measurements) (Details) - Discounted Cash Flow [Member] | 12 Months Ended
--- | ---
Dec. 31, 2018
Auction Rate Equity Securities [Member] |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |
Workout period range, low end | 2 years
Workout period range, high end | 3 years
Discount rate, weighted average | 3.20%
Weighted average workout period | 2 years 4 months 24 days
Auction Rate Equity Securities [Member] | Minimum [Member] |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |
Discount rate range | 0.00%
Auction Rate Equity Securities [Member] | Maximum [Member] |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |
Discount rate range | 5.60%
Auction Rate Municipal Securities [Member] |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |
Workout period range, low end | 1 year
Workout period range, high end | 4 years
Discount rate, weighted average | 2.80%
Weighted average workout period | 2 years
Auction Rate Municipal Securities [Member] | Minimum [Member] |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |
Discount rate range | 0.70%
Auction Rate Municipal Securities [Member] | Maximum [Member] |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |
Discount rate range | 8.30%

X
- Definition Weighted average workout period. + References No definition available. + Details
Name: | sf_WeightedAverageWorkoutPeriod
Namespace Prefix: | sf_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Workout period range, high end. + References No definition available. + Details
Name: | sf_WorkoutPeriodRangeHighEnd
Namespace Prefix: | sf_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Workout period range, low end. + References No definition available. + Details
Name: | sf_WorkoutPeriodRangeLowEnd
Namespace Prefix: | sf_
Data Type: | xbrli:durationItemType
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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The discount rate used to reduce the estimated amount of loss reserves on short-duration contracts to present value. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 5.N.Q1) -URI http://asc.fasb.org/extlink&oid=27015749&loc=d3e569934-122904 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=99384497&loc=d3e14881-158438 + Details
Name: | us-gaap_ShortDurationContractsDiscountedLiabilitiesDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The average discount rate applied to insurance contracts to determine future policy benefits to be paid to or on behalf of policyholders. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=99384497&loc=d3e14881-158438 + Details
Name: | us-gaap_WeightedAverageDiscountRatePercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=sf_DiscountedCashFlowMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=sf_MunicipalSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |