Segment Information - Additional Information (Detail)	12 Months Ended
Dec. 31, 2012 Segment
Segment Reporting Information [Line Items]
Number of operating segments	3

Number of operating segments previously reported in prior year audited financial statements.

No definition available.

Name:	gsig_NumberOfPreviousOperatingSegments
Namespace Prefix:	gsig_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration