XML 114 R19.htm IDEA: XBRL DOCUMENT v2.4.0.6

Capital Stock	12 Months Ended
	Dec. 31, 2012
Capital Stock [Abstract]
Capital Stock	12. Capital Stock Common Stock The Company is authorized to issue 50,000,000 shares of common stock, par value $0.01 per share. At December 31, 2012, there were 19,513,476 shares of common stock issued and 18,255,226 shares outstanding. Preferred Stock Shareholders approved an amended Certificate of Formation for the Company on June 15, 2010 under which the Company is authorized to issue 10,000,000 shares of preferred stock, par value $0.01 per share. At December 31, 2012, there were no shares of preferred stock outstanding. No shares of these classes of capital stock were outstanding at December 31, 2012 or 2011. No shares of these classes of capital stock were issued in the three year period ended December 31, 2012. Effective December 31, 2009, all outstanding shares of Series C preferred stock and Series D preferred stock were redeemed and canceled.

X

- Details

Name:	amsf_CapitalStockAbstract
Namespace Prefix:	amsf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Capital stock text block.

+ References

No definition available.

+ Details

Name:	amsf_CapitalStockTextBlock
Namespace Prefix:	amsf_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration