Name:	sf_FinancialInstrumentsOwnedOtherAtFairValue2
Namespace Prefix:	sf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Investments in notes or bonds that are collateralized by a specific group of underlying assets owned by the issuer of the notes or bonds which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

No definition available.

Name:	us-gaap_AssetBackedSecuritiesAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Fair value of firm holdings in securities classified as other. Includes pledged and unpledged holdings.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 320
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35711157&loc=d3e42546-110969

Name:	us-gaap_FinancialInstrumentsOwnedOtherAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The fair value as of the balance sheet date of firm holdings in fixed income obligations issued by foreign governments. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

Name:	us-gaap_FinancialInstrumentsOwnedOtherSovereignGovernmentObligationsAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Fair value of obligations arising from corporate debt obligations sold short.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 320
-Section 35
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35711043&loc=d3e42429-110968

Name:	us-gaap_FinancialInstrumentsSoldNotYetPurchasedCorporateDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Fair value of obligations arising from state and municipal debt obligations sold short.

Name:	us-gaap_FinancialInstrumentsSoldNotYetPurchasedStateAndMunicipalGovernmentObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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.

No definition available.

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

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Name:	us-gaap_TradingSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121553693&loc=d3e26610-111562

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121553693&loc=d3e26610-111562

Name:	us-gaap_TradingSecuritiesDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Fair value of investments in trading equity securities and other forms of trading securities that provide ownership interests.

No definition available.

Name:	us-gaap_TradingSecuritiesEquity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_FixedIncomeSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FairValueByAssetClassAxis=sf_CorporateEquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_LoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_SecurityOwnedAndSoldNotYetPurchasedAtFairValueAxis=us-gaap_USGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_UnderlyingAssetClassAxis=us-gaap_SovereignDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FairValueByLiabilityClassAxis=us-gaap_SecuritiesSoldNotYetPurchasedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_UnderlyingAssetClassAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_AgencySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: