Property, Plant and Equipment (Details Textuals 1) (Capital Lease Obligations, USD $)	Jun. 30, 2012
Land And Building \| Elma
Property, Plant and Equipment [Line Items]
Aggregate Nominal Amount Of Assets Under Capital Leases	$ 5,000,000
Machinery and equipment
Property, Plant and Equipment [Line Items]
Capital Lease Obligations Related Party	$ 588,000

Total nominal amount of assets under capital leases.

No definition available.

Name:	svt_AggregateNominalAmountOfAssetsUnderCapitalLeases
Namespace Prefix:	svt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant