v2.4.0.6

Segments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Specialty Risk and Extended Warranty
Segment Reporting Information [Line Items]
Gross written premium	$ 125,900
Specialty Program
Segment Reporting Information [Line Items]
Gross written premium	$ 87,150

X

- Definition

Premiums Written, Gross, from Broker

+ References

No definition available.

+ Details

Name:	afsi_PremiumsWrittenGrossFromBroker
Namespace Prefix:	afsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

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