Annual report pursuant to Section 13 and 15(d)

Related Party Transactions - Additional Information (Detail)

v2.4.1.9
Related Party Transactions - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Related Party Transaction [Line Items]      
Equity income from investments $ 1,208us-gaap_IncomeLossFromEquityMethodInvestments $ 21us-gaap_IncomeLossFromEquityMethodInvestments $ 1,911us-gaap_IncomeLossFromEquityMethodInvestments
Performance fees and allocations 221us-gaap_PerformanceFees 1,830us-gaap_PerformanceFees 714us-gaap_PerformanceFees
Due from Silvercrest Funds 3,797us-gaap_DueFromRelatedParties 2,653us-gaap_DueFromRelatedParties  
General and administrative expense 13,860us-gaap_GeneralAndAdministrativeExpense 13,197us-gaap_GeneralAndAdministrativeExpense 13,680us-gaap_GeneralAndAdministrativeExpense
Affiliated Entity      
Related Party Transaction [Line Items]      
Income from management fees 8,974us-gaap_AssetManagementFees1
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
8,994us-gaap_AssetManagementFees1
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
8,484us-gaap_AssetManagementFees1
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
Income from performance fees and allocations 1,417samg_PerformanceFeesAndAllocations
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
14samg_PerformanceFeesAndAllocations
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
2,615samg_PerformanceFeesAndAllocations
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
Equity income from investments 1,196us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
14us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
1,901us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
Performance fees and allocations 221us-gaap_PerformanceFees
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
0us-gaap_PerformanceFees
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
714us-gaap_PerformanceFees
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
Due from Silvercrest Funds 3,797us-gaap_DueFromRelatedParties
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
2,653us-gaap_DueFromRelatedParties
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
 
Income from advisory fees 592us-gaap_InvestmentAdvisoryFees
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
479us-gaap_InvestmentAdvisoryFees
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
408us-gaap_InvestmentAdvisoryFees
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
Receivable from partners 2us-gaap_AccountsReceivableRelatedParties
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
78us-gaap_AccountsReceivableRelatedParties
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
 
Affiliated Entity | Minimum      
Related Party Transaction [Line Items]      
Management and advisory fees percentage 0.00%samg_ManagementAndAdvisoryFeesPercentage
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
   
Percentage of performance fees 0.00%samg_PercentageOfPerformanceFees
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
   
Affiliated Entity | Maximum      
Related Party Transaction [Line Items]      
Management and advisory fees percentage 1.75%samg_ManagementAndAdvisoryFeesPercentage
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
   
Percentage of performance fees 10.00%samg_PercentageOfPerformanceFees
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_AffiliatedEntityMember
   
Death of Chief Executive Officer      
Related Party Transaction [Line Items]      
General and administrative expense   780us-gaap_GeneralAndAdministrativeExpense
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_ChiefExecutiveOfficerMember
 
Proceeds from Life Insurance Policies   $ 3,010us-gaap_ProceedsFromLifeInsurancePolicies
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_ChiefExecutiveOfficerMember