Net Income Per Common Share - Additional Information (Detail) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Income Loss Per Common Share
Exercise of stock options	0.4	0.3	0.7
Restricted stock units exercise to purchase shares		0.3

Issuance of ordinary shares upon exercise of employee stock options and restricted stock units, shares.

No definition available.

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