Revenue Recognition (Details)	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Revenue Recognition
Percentage of revenues from governmental healthcare programs	25.00%	27.00%

Percent healthcare revenues governmental programs.

No definition available.

Name:	amsg_PercentHealthcareRevenuesGovernmentalPrograms
Namespace Prefix:	amsg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration