v2.4.0.6

Fair Values of Restricted Assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investments, Debt and Equity Securities [Abstract]
Restricted cash	$ 46,795	$ 23,104
Restricted investments	292,941	187,227
Total restricted cash and investments	$ 339,736	$ 210,331

X

- Definition

Restricted Cash and Cash Equivalents, Fair Value Disclosure

+ References

No definition available.

+ Details

Name:	afsi_RestrictedCashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	afsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Restricted Cash and Investments Fair Value Disclosure

+ References

No definition available.

+ Details

Name:	afsi_RestrictedCashAndInvestmentsFairValueDisclosure
Namespace Prefix:	afsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The aggregate value of all restricted investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 12

-Paragraph 6

-Subparagraph c

-Article 12



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 320

-Section S99

-Paragraph 4

-Subparagraph (SX 210.12-12C.9(c))

-URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611225-123010



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 320

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-12.6(c))

-URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611133-123010



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 12C

-Paragraph 9

-Subparagraph c

-Article 12

+ Details

Name:	us-gaap_RestrictedInvestmentsAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant