Operating Segment Geographic and Significant Customer Information - Additional Information (Detail)	12 Months Ended
Dec. 31, 2012 Customer	Dec. 31, 2011 Customer	Dec. 31, 2010 Customer
Segment Reporting Information [Line Items]
Number of customer accounted for more than consolidated revenue	1	0	0
Major customer, approximate percentage of total revenue	10.00%	10.00%	10.00%

Percent of total consolidated revenue accounted for by major customer for segment reporting

No definition available.

Name:	ter_SegmentReportingMajorCustomersPercentRevenue
Namespace Prefix:	ter_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration