Annual report pursuant to Section 13 and 15(d)

Acquisitions - Summary of Pro Forma Information (Detail)

v2.4.1.9
Acquisitions - Summary of Pro Forma Information (Detail) (Ten-Sixty, USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Ten-Sixty
   
Business Acquisition [Line Items]    
Total Revenue $ 60,279us-gaap_BusinessAcquisitionsProFormaRevenue
/ us-gaap_BusinessAcquisitionAxis
= samg_TenSixtyAssetManagementLlcMember
$ 52,390us-gaap_BusinessAcquisitionsProFormaRevenue
/ us-gaap_BusinessAcquisitionAxis
= samg_TenSixtyAssetManagementLlcMember
Net Income $ 17,220us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= samg_TenSixtyAssetManagementLlcMember
$ 19,846us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= samg_TenSixtyAssetManagementLlcMember