Annual report pursuant to Section 13 and 15(d)

Consolidated Statements of Changes in Stockholder's Equity/Partners' Deficit

v2.4.1.9
Consolidated Statements of Changes in Stockholder's Equity/Partners' Deficit (USD $)
In Thousands, except Share data
Total
Additional Paid-In Capital
Retained Earnings
Total Stockholders' Equity
Non-controlling Interest
Partners' Capital
Excess Of Liabilities, Redeemable Partners' Capital And Partners' Capital Over Assets
Total Partners' Deficit
Class A Common Stock
Class B Common Stock
Balance at Dec. 31, 2011           $ 44,359us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersCapitalMember
$ (100,025)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
$ (55,666)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Contributions from partners             112us-gaap_PartnersCapitalAccountContributions
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
112us-gaap_PartnersCapitalAccountContributions
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Distributions to partners           (1,466)us-gaap_LimitedPartnersCapitalAccountDistributionAmount
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersCapitalMember
(13,283)us-gaap_LimitedPartnersCapitalAccountDistributionAmount
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
(14,749)us-gaap_LimitedPartnersCapitalAccountDistributionAmount
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Issuance of notes receivable by partners (112)samg_NotesReceivableFromNewPartnersIssuedAsCapitalContribution                  
Equity-based compensation             1,019us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
1,019us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Accretion to redemption value of redeemable partnership units             (10,906)us-gaap_TemporaryEquityAccretionToRedemptionValue
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
(10,906)us-gaap_TemporaryEquityAccretionToRedemptionValue
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Net Income 19,720us-gaap_ProfitLoss         5,011us-gaap_ProfitLoss
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersCapitalMember
14,709us-gaap_ProfitLoss
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
19,720us-gaap_ProfitLoss
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Balance at Dec. 31, 2012           47,904us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersCapitalMember
(108,374)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
(60,470)us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Contributions from partners 165us-gaap_PartnersCapitalAccountContributions       165us-gaap_PartnersCapitalAccountContributions
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  455us-gaap_PartnersCapitalAccountContributions
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
455us-gaap_PartnersCapitalAccountContributions
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Contributions from partners, Shares                   17,000us-gaap_PartnersCapitalAccountUnitsContributed
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Distributions to partners (1,417)us-gaap_LimitedPartnersCapitalAccountDistributionAmount       (1,417)us-gaap_LimitedPartnersCapitalAccountDistributionAmount
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
(4,036)us-gaap_LimitedPartnersCapitalAccountDistributionAmount
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersCapitalMember
(23,864)us-gaap_LimitedPartnersCapitalAccountDistributionAmount
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
(27,900)us-gaap_LimitedPartnersCapitalAccountDistributionAmount
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Issuance of notes receivable by partners (455)samg_NotesReceivableFromNewPartnersIssuedAsCapitalContribution                  
Accrued partner incentive distributions             (6,000)us-gaap_IncentiveDistributionDistributionPerYear
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
(6,000)us-gaap_IncentiveDistributionDistributionPerYear
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Redemptions of partners’ interests (190)us-gaap_PartnersCapitalAccountRedemptions       (190)us-gaap_PartnersCapitalAccountRedemptions
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  (5,561)us-gaap_PartnersCapitalAccountRedemptions
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
(5,561)us-gaap_PartnersCapitalAccountRedemptions
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Redemptions of partners' interests, Shares                   (14,000)us-gaap_PartnersCapitalAccountUnitsRedeemed
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Equity-based compensation 635us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue       635us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
  1,024us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
1,024us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Equity-based compensation, Shares                   16,000us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Net Income 17,168us-gaap_ProfitLoss                  
Reclassification of equity-based awards due to elimination of redemption feature             824samg_ReclassificationOfEquityBasedAwardsDueToEliminationOfRedemptionFeature
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
824samg_ReclassificationOfEquityBasedAwardsDueToEliminationOfRedemptionFeature
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Net Income 6,239samg_PreIPONetIncomeLoss   2,760samg_PreIPONetIncomeLoss
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
2,760samg_PreIPONetIncomeLoss
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
3,479samg_PreIPONetIncomeLoss
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
2,827samg_PreIPONetIncomeLoss
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersCapitalMember
8,102samg_PreIPONetIncomeLoss
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
10,929samg_PreIPONetIncomeLoss
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
   
Issuance of Class A shares in IPO 55,215us-gaap_StockIssuedDuringPeriodValueNewIssues 55,160us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
  55,215us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
        55us-gaap_StockIssuedDuringPeriodValueNewIssues
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
 
Issuance of Class A shares in IPO, Shares                 5,509,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
 
Reorganization of equity structure 12,783samg_ReorganizationOfEquityStructureValue     100samg_ReorganizationOfEquityStructureValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
12,683samg_ReorganizationOfEquityStructureValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
(46,695)samg_ReorganizationOfEquityStructureValue
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersCapitalMember
133,394samg_ReorganizationOfEquityStructureValue
/ us-gaap_StatementEquityComponentsAxis
= samg_ExcessOfLiabilitiesRedeemablePartnersCapitalAndPartnersCapitalOverAssetsMember
86,699samg_ReorganizationOfEquityStructureValue
/ us-gaap_StatementEquityComponentsAxis
= samg_PartnersDeficitMember
  100samg_ReorganizationOfEquityStructureValue
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Reorganization of equity structure, Shares                   10,000,000samg_ReorganizationOfEquityStructureShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Purchase of Class B units of SLP (35,400)us-gaap_StockRedeemedOrCalledDuringPeriodValue (30,881)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
  (30,916)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
(4,484)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
        (35)us-gaap_StockRedeemedOrCalledDuringPeriodValue
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Purchase of Class B units of SLP, Shares                   (3,541,000)us-gaap_StockRedeemedOrCalledDuringPeriodShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Accrued interest on notes receivable from partners (30)samg_AccruedInterestOnNotesReceivable       (30)samg_AccruedInterestOnNotesReceivable
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
         
Share Conversion, Value   3,898samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
  3,898samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
(3,898)samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
      20samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
(20)samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Share Conversion, Shares                 2,013,000samg_StockIssuedDuringPeriodSharesConversionOfConvertibleShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
(2,013,677)samg_StockIssuedDuringPeriodSharesConversionOfConvertibleShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Dividends paid on Class A common stock (661)us-gaap_DividendsCommonStockCash   (661)us-gaap_DividendsCommonStockCash
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
(661)us-gaap_DividendsCommonStockCash
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
           
Initial establishment of deferred tax assets, net of amounts payable under tax receivable agreement 10,826samg_InitialEstablishmentOfDeferredTaxAssetsNetOfAmountsPayableUnderTaxReceivableAgreement 10,826samg_InitialEstablishmentOfDeferredTaxAssetsNetOfAmountsPayableUnderTaxReceivableAgreement
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
  10,826samg_InitialEstablishmentOfDeferredTaxAssetsNetOfAmountsPayableUnderTaxReceivableAgreement
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
           
Balance at Dec. 31, 2013 48,165us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest 39,003us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
2,099us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
41,222us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
6,943us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
      75us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
45us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Balance, Shares at Dec. 31, 2013                 7,522,974us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
4,464,617us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Balance at Jul. 10, 2013                    
Issuance of Class A shares in IPO, Shares                 718,603us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
 
Balance, Shares at Jul. 12, 2013                 5,509,297us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
 
Balance at Dec. 31, 2013 48,165us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest 39,003us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
2,099us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
41,222us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
6,943us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
      75us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
45us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Balance, Shares at Dec. 31, 2013                 7,522,974us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
4,464,617us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Contributions from partners 941us-gaap_PartnersCapitalAccountContributions     1us-gaap_PartnersCapitalAccountContributions
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
940us-gaap_PartnersCapitalAccountContributions
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
        1us-gaap_PartnersCapitalAccountContributions
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Contributions from partners, Shares                   60,000us-gaap_PartnersCapitalAccountUnitsContributed
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Distributions to partners (5,242)us-gaap_LimitedPartnersCapitalAccountDistributionAmount       (5,242)us-gaap_LimitedPartnersCapitalAccountDistributionAmount
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
         
Issuance of notes receivable by partners (940)samg_NotesReceivableFromNewPartnersIssuedAsCapitalContribution       (940)samg_NotesReceivableFromNewPartnersIssuedAsCapitalContribution
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
         
Redemptions of partners’ interests (376)us-gaap_PartnersCapitalAccountRedemptions       (376)us-gaap_PartnersCapitalAccountRedemptions
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
         
Redemptions of partners' interests, Shares                   (23,000)us-gaap_PartnersCapitalAccountUnitsRedeemed
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Adjustment of partner redemption obligation (Note 9) 1,583samg_AdjustmentOfPartnersEquityRedemptionObligation       1,583samg_AdjustmentOfPartnersEquityRedemptionObligation
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
         
Equity-based compensation 1,533us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue     3us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
1,530us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
        3us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Equity-based compensation, Shares                   264,000us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Net Income 10,708us-gaap_ProfitLoss   4,775us-gaap_ProfitLoss
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
4,775us-gaap_ProfitLoss
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
5,933us-gaap_ProfitLoss
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
         
Issuance of Class A shares in IPO, Shares                   261,958us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Accrued interest on notes receivable from partners (61)samg_AccruedInterestOnNotesReceivable       (61)samg_AccruedInterestOnNotesReceivable
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
         
Share Conversion, Value 23samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares 628samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
  628samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
(605)samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
      3samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
(3)samg_StockIssuedDuringPeriodValueConversionOfConvertibleShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Share Conversion, Shares                 246,000samg_StockIssuedDuringPeriodSharesConversionOfConvertibleShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
(246,000)samg_StockIssuedDuringPeriodSharesConversionOfConvertibleShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Dividends paid on Class A common stock (3,657)us-gaap_DividendsCommonStockCash   (3,657)us-gaap_DividendsCommonStockCash
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
(3,657)us-gaap_DividendsCommonStockCash
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
           
Repayment of notes receivable from partners 841samg_IncreaseFromNotesReceivableFromRelatedParties       841samg_IncreaseFromNotesReceivableFromRelatedParties
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
         
Deferred tax, net of amounts payable under tax receivable agreement (456)samg_AdjustmentsToAdditionalPaidInCapitalDeferredTax (456)samg_AdjustmentsToAdditionalPaidInCapitalDeferredTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
  (456)samg_AdjustmentsToAdditionalPaidInCapitalDeferredTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
           
Balance at Dec. 31, 2014 $ 53,062us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest $ 39,175us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AdditionalPaidInCapitalMember
$ 3,217us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_RetainedEarningsMember
$ 42,516us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_ParentMember
$ 10,546us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
      $ 78us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
$ 46us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
Balance, Shares at Dec. 31, 2014                 7,768,010us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
4,520,413us-gaap_CommonStockSharesOutstanding
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember