Net Income Per Common Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended
Mar. 30, 2025	Mar. 31, 2024
Employee Stock Option [Member]
Net Income Loss Per Common Share
Exercise of stock options	0.5	0.4

Stock issued during period shares sale of stock and exercise of stock options.

No definition available.

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