Accumulated Other Comprehensive Loss - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 28, 2012	Sep. 30, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassified Accumulated Other Comprehensive Loss Into Net Income	$ 0.6	$ 0.2

Reclassification of defined benefit plan transition obligation and amortization of net prior service cost recognized into net income.

No definition available.

Name:	gsig_OtherComprehensiveIncomeReclassificationIntoNetIncome
Namespace Prefix:	gsig_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration