Net Income Per Common Share - Additional Information (Detail) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 29, 2014	Jun. 30, 2013	Jun. 29, 2014	Jun. 30, 2013
Net Income Loss Per Common Share
Exercise of stock options	0.3	0.5	0.3	0.5

Stock Issued During Period Shares Sale Of Stock And Exercise Of Stock Options

No definition available.

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Namespace Prefix:	ter_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration