Commitments and Contingencies - Additional Information (Detail) In Millions, unless otherwise specified	1 Months Ended			12 Months Ended						12 Months Ended					1 Months Ended	3 Months Ended
	Jul. 13, 2010 USD ($)	May 27, 2010	Nov. 20, 2009	Dec. 31, 2012 USD ($) Customer	Dec. 31, 2011 USD ($) Customer	Dec. 31, 2010 USD ($)	May 06, 2011 EUR (€)	Apr. 18, 2006 EUR (€)	May 06, 2011 GSI Group GmbH EUR (€)	Dec. 31, 2012 Minimum	Dec. 31, 2012 Maximum USD ($)	Dec. 31, 2012 Land Maximum	Dec. 31, 2012 Internal Revenue Service (IRS)	Apr. 05, 2010 Internal Revenue Service (IRS) USD ($)	Apr. 18, 2006 GSI's French Subsidiary	Sep. 30, 2005 GSI's French Subsidiary
Commitments and Contingencies Disclosure [Line Items]
Lease agreement expiration year										2013	2019	2078
Lease expense				$ 4.4	$ 3.6	$ 3.6
Asset capitalized under capital lease					2.2
Unconditional purchase commitments				24.3
Unconditional purchase commitments, 2013				24.1
Unconditional purchase commitments, 2014				0.2
Unconditional purchase commitments, 2015											0.1
Filed for bankruptcy protection date			Nov. 20, 2009													Jul. 07, 2005
Actions taken		On May 27, 2010, the Bankruptcy Court entered an order confirming and approving the plan of reorganization (the "Final Chapter 11 Plan").													On April 18, 2006, the commercial court of Le Creusot (France) ordered GSI France to pay approximately 0.7 million Euros to SCGI in the context of a claim filed by SCGI that a Laserdyne 890 system delivered in 1999 had unresolved technical problems.
Payment to settle claim filed, minimum								0.7
Payment to settle claim filed, maximum							3.1
Payment in the respect of a claim filed									2.4
IRS filed amended proofs of claim date													April 5, 2010
IRS filed aggregate claims														7.7
IRS Claims	On July 13, 2010, the Company filed a complaint, GSI Group Corporation v. United States of America, in Bankruptcy Court in an attempt to recover refunds totaling approximately $18.8 million in federal income taxes the Company asserts it overpaid to the IRS relating to tax years 2000 through 2008, together with applicable interest.
Amount of claim we filed with the IRS for federal income taxes overpaid	$ 18.8
Number of customer accounted on accounts receivable balance				1
Number of customers accounted for 10% or more of accounts receivable				0	0