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Fair Value Of Financial Instruments (Schedule Of Changes In Fair Value Carrying Values Associated With Level 3 Financial Instruments) (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance $ 6,200us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue  
Unrealized gains/(losses), Included in OCI, Assets 62us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss  
Transfers, Out of Level 3 (6,262)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3  
Net change (6,200)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease  
Mortgage-backed securities [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Unrealized gains/(losses), Included in changes in net assets (127)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_MortgageBackedSecuritiesMember		  
Realized gains/(losses), Assets 13sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisRealizedAssetGainLossIncludedInEarnings
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_MortgageBackedSecuritiesMember		  
Redemptions (44)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_MortgageBackedSecuritiesMember		  
Transfers, Into Level 3 964us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_MortgageBackedSecuritiesMember		  
Net change 806us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_MortgageBackedSecuritiesMember		  
Ending Balance 806us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_MortgageBackedSecuritiesMember		  
Corporate Fixed Income Securities [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance 2,039us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 583us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember
Unrealized gains/(losses), Included in changes in net assets (445)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 779us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 [1]
Realized gains/(losses), Assets (1,320)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisRealizedAssetGainLossIncludedInEarnings
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 281sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisRealizedAssetGainLossIncludedInEarnings
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 [1]
Purchases 8,549us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 10,261us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember
Sales (5,783)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 (6,888)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember
Redemptions (88)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 (1,349)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember
Transfers, Into Level 3   139us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember
Transfers, Out of Level 3 (959)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 (1,767)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember
Net change (46)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 1,456us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember
Ending Balance 1,993us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember		 2,039us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_FixedIncomeSecuritiesMember
Equity Securities [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance 241us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember		  
Unrealized gains/(losses), Included in changes in net assets (494)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember		 1,333us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember		 [1]
Realized gains/(losses), Assets 4,965sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisRealizedAssetGainLossIncludedInEarnings
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember		  
Purchases 1,394us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember		 11,717us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember
Sales (5,205)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember		 (208)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember
Transfers, Into Level 3 243us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember		  
Transfers, Out of Level 3   (12,601)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember
Net change 903us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember		 241us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember
Ending Balance 1,144us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember		 241us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_TradingEquitySecuritiesMember
State And Municipal Securities [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance   90,487us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Unrealized gains/(losses), Included in OCI, Assets   (1,822)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		 [1]
Realized gains/(losses), Assets   2,053sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisRealizedAssetGainLossIncludedInEarnings
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember		 [1]
Purchases   5,000us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Redemptions   (32,000)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Transfers, Into Level 3   6,201us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Transfers, Out of Level 3   (63,719)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Net change   (84,287)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Ending Balance   6,200us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Asset-Backed Securities [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance 58,078us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember		  
Unrealized gains/(losses), Included in changes in net assets   (233)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember		 [1]
Unrealized gains/(losses), Included in OCI, Assets (530)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember		  
Realized gains/(losses), Assets 1,322sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisRealizedAssetGainLossIncludedInEarnings
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember		  
Sales (4,825)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember		  
Redemptions (10,000)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember		  
Transfers, Into Level 3   58,311us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember
Net change (14,033)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember		 58,078us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember
Ending Balance 44,054us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember		 58,078us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AssetBackedSecuritiesMember
Equity Auction Rate Securities [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance 56,693us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember		 64,397us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember
Unrealized gains/(losses), Included in changes in net assets 604us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember		 571us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember		 [1]
Purchases 25us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember		 75us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember
Sales (1,725)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember		  
Redemptions (9,400)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember		 (8,350)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember
Net change (10,496)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember		 (7,704)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember
Ending Balance 46,197us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember		 56,693us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_AuctionRateSecuritiesMember
Municipal Auction Rate Securities [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance 10,939us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember		 14,067us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember
Unrealized gains/(losses), Included in changes in net assets 688us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember		 75us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember		 [1]
Purchases 1,650us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember		  
Sales (10,324)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember		  
Redemptions (1,627)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember		 (3,203)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember
Net change (9,613)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember		 (3,128)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember
Ending Balance 1,326us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember		 10,939us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_AuctionRateMunicipalSecuritiesMember
Other Investment [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Beginning Balance 97,768us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [2] 37,297us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [2]
Unrealized gains/(losses), Included in changes in net assets 903us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 6,328us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [1],[2]
Realized gains/(losses), Assets 3,290sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisRealizedAssetGainLossIncludedInEarnings
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 13sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisRealizedAssetGainLossIncludedInEarnings
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [1],[2]
Purchases 1,263us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 50,914us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [2]
Sales (22,058)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 (6,801)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [2]
Redemptions (4,294)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 (2,584)sf_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRedemptions
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [2]
Transfers, Into Level 3   12,601us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [2]
Transfers, Out of Level 3 (3,882)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		  
Net change (24,778)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 60,471us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPeriodIncreaseDecrease
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [2]
Ending Balance $ 72,990us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 $ 97,768us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
/ us-gaap_FairValueByAssetClassAxis
= sf_OtherInvestmentMember		 [2]
[1] Realized and unrealized gains/(losses) related to financial instruments owned and investments are reported in other income in the consolidated statements of operations.
[2] Includes partnership interests, private company investments, and private equity investments.