XML 62 R97.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Subsequent Events (Details) (Subsequent Event [Member], USD $) | Mar. 28, 2013 | Dec. 31, 2012
--- | --- | ---
Subsequent Event [Member] |  |
Subsequent Events (Textual) [Abstract] |  |
Cash dividend per share | $ 0.08 |
Expected cash dividend per share |  | $ 0.32

X
- Definition Expected cash dividend per share. + References No definition available. + Details
Name: | amsf_ExpectedCashDividendPerShare
Namespace Prefix: | amsf_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition The per share amount of a dividend declared, but not paid, as of the financial reporting date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 32 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_DividendsPayableAmountPerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant