Leases (Parenthetical) (Details)	12 Months Ended
Dec. 31, 2012
Maximum [Member]
Capital Lease Interest Rate Range [Line Items]
Capital Lease Interest Rates	11.80%
Minimum [Member]
Capital Lease Interest Rate Range [Line Items]
Capital Lease Interest Rates	3.80%

Interest rates applicable to leases that are treated as capital.

No definition available.

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