Schedule of Restricted Stock Unit Awards Aggregate Intrinsic Value (Detail) (Restricted Stock Units, USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Outstanding	$ 81,680	$ 83,949	$ 79,598
Expected to vest	$ 77,388	$ 78,718	$ 75,860

Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested And Expected To Vest Intrinsic Value

No definition available.

Name:	ter_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestIntrinsicValue
Namespace Prefix:	ter_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant