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Income Taxes - Summary of Reconciles Provision for Income Taxes (Detail)
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12 Months Ended | ||
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Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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| Reconciliation of federal statutory tax rate to effective rate | |||
| Statutory U.S. federal income tax rate | 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate | 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate | 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate |
| Income passed through to Partners | (12.43%)us-gaap_EffectiveIncomeTaxRateReconciliationDeductionsDividends | (25.57%)us-gaap_EffectiveIncomeTaxRateReconciliationDeductionsDividends | (35.00%)us-gaap_EffectiveIncomeTaxRateReconciliationDeductionsDividends |
| State and local income taxes | 15.60%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes | 6.92%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes | 5.26%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes |
| Permanent items | (3.69%)samg_EffectiveIncomeTaxRateReconciliationPermanentItems | 0.00%samg_EffectiveIncomeTaxRateReconciliationPermanentItems | 0.00%samg_EffectiveIncomeTaxRateReconciliationPermanentItems |
| Life insurance proceeds | 0.00%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseLifeInsurance | (5.41%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseLifeInsurance | 0.00%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseLifeInsurance |
| Other | 2.87%us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments | 0.13%us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments | (0.17%)us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments |
| Effective income tax rate | 37.35%us-gaap_EffectiveIncomeTaxRateContinuingOperations | 11.07%us-gaap_EffectiveIncomeTaxRateContinuingOperations | 5.09%us-gaap_EffectiveIncomeTaxRateContinuingOperations |
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- Definition
Effective income tax rate reconciliation permanent items. No definition available.
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- Definition
Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deduction for dividend. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to life insurance expense. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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