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Computation of Basic and Diluted Net Income (loss) Per Common Share (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 9 Months Ended
Oct. 01, 2017
Oct. 02, 2016
Oct. 01, 2017
Oct. 02, 2016
Net Income Loss Per Common Share        
Net income (loss) for basic and diluted net income (loss) per share $ 103,420 $ 63,794 $ 363,616 $ (109,767)
Weighted average common shares-basic 197,485 202,211 198,755 203,167
Incremental shares from assumed conversion of convertible note [1] 1,144   632  
Employee stock purchase plan 8 15 26  
Dilutive potential common shares 3,290 1,718 2,658  
Weighted average common shares-diluted 200,775 203,929 201,413 203,167
Net income (loss) per common share-basic $ 0.52 $ 0.32 $ 1.83 $ (0.54)
Net income (loss) per common share-diluted $ 0.52 $ 0.31 $ 1.81 $ (0.54)
Restricted Stock Units        
Net Income Loss Per Common Share        
Incremental shares attributable to share based payment arrangements 1,832 1,282 1,663  
Stock Options        
Net Income Loss Per Common Share        
Incremental shares attributable to share based payment arrangements 306 421 337  
[1] Incremental shares from assumed conversion of the convertible notes for the three and nine months ended October 1, 2017 are calculated using the difference between the average Teradyne stock price for the period and the conversion price of $31.84, multiplied by the 14.4 million shares that would be issued upon conversion. The result of this calculation, representing the total intrinsic value of the convertible debt, is divided by the average Teradyne stock price for the period.