Quarterly report pursuant to Section 13 or 15(d)

Notes Receivable from Partners - Additional Information (Detail)

v2.4.1.9
Notes Receivable from Partners - Additional Information (Detail) (Partners, USD $)
3 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Aug. 31, 2009
Jan. 31, 2008
Related Party Transaction [Line Items]          
Term of promissory notes receivable in the form of five or six year interest-bearing promissory notes and/or in the form of nine year interest-bearing limited recourse promissory notes        
Notes receivable from partners $ 2,749,000us-gaap_NotesReceivableNet $ 3,212,000us-gaap_NotesReceivableNet $ 3,052,000us-gaap_NotesReceivableNet    
Allowance for credit losses on notes receivable 0us-gaap_FinancingReceivableAllowanceForCreditLosses 0us-gaap_FinancingReceivableAllowanceForCreditLosses      
Limited Recourse
         
Related Party Transaction [Line Items]          
Interest rates of promissory notes       2.77%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= samg_LimitedRecourseMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= samg_GeneralPartnerAndLimitedPartnerMember
3.53%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= samg_LimitedRecourseMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= samg_GeneralPartnerAndLimitedPartnerMember
Notes receivable from partners 1,195,000us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= samg_LimitedRecourseMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= samg_GeneralPartnerAndLimitedPartnerMember
1,300,000us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= samg_LimitedRecourseMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= samg_GeneralPartnerAndLimitedPartnerMember
     
Full Recourse
         
Related Party Transaction [Line Items]          
Notes receivable from partners $ 1,554,000us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= samg_FullRecourseMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= samg_GeneralPartnerAndLimitedPartnerMember
$ 1,912,000us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= samg_FullRecourseMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= samg_GeneralPartnerAndLimitedPartnerMember