v2.4.0.6

Fair Value of Portfolio of Life Insurance Policies (Detail) (USD $) In Thousands, unless otherwise specified | 9 Months Ended
--- | ---
Sep. 30, 2012 | Dec. 31, 2011
Disclosure Fair Value Of Portfolio Of Life Insurance Policies [Abstract] |  |  |  |
Average age of insured | 79 years |  | 77 years |
Average life expectancy, months | 143 months | [1] | 155 months | [1]
Average face amount per policy | $ 6,818 |  | $ 6,703 |
Fair value discount rate | 7.50% |  | 7.50% |
Internal rate of return | 15.90% | [2] | 14.10% | [2]
[1] | Standard life expectancy as adjusted for insured’s specific circumstances.
[2] | Internal rate of return includes a risk premium which represents risk adjustments applied to the estimated present value of cash flows based on the following factors: (i) the volatility in life expectancy of insureds and the associated level of future premium payments and (ii) the projected risk of non-payment, including the financial health of the insurance carrier, the possibility of legal challenges from the insurance carrier or others and the possibility of regulatory changes that may affect payment.

X
- Details
Name: | afsi_DisclosureFairValueOfPortfolioOfLifeInsurancePoliciesAbstract
Namespace Prefix: | afsi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Internal Rate of Return + References No definition available. + Details
Name: | afsi_InternalRateOfReturn
Namespace Prefix: | afsi_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Life Settlement Contracts Fair Value Method Average Age of Insured + References No definition available. + Details
Name: | afsi_LifeSettlementContractsFairValueMethodAverageAgeOfInsured
Namespace Prefix: | afsi_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Life Settlement Contracts, Fair Value Method, Average Face Value Per Contract + References No definition available. + Details
Name: | afsi_LifeSettlementContractsFairValueMethodAverageFaceValuePerContract
Namespace Prefix: | afsi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Life Settlement Contracts Fair Value Method Average Life Expectancy + References No definition available. + Details
Name: | afsi_LifeSettlementContractsFairValueMethodAverageLifeExpectancy
Namespace Prefix: | afsi_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueInputsDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration