Schedule of Segment Reporting Information by Segment Charges (Detail) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended															12 Months Ended
		Jan. 31, 2014	Dec. 31, 2016		Oct. 02, 2016		Jul. 03, 2016		Apr. 03, 2016		Dec. 31, 2015		Oct. 04, 2015		Jul. 05, 2015		Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Goodwill impairment charge			$ 0				$ 254,946	[1],[2]									$ 98,897	$ 254,946	$ (254,946)	$ 98,897
Acquired intangible assets impairment charge							83,339	[1],[2]										83,339	98,200
Restructuring and other			5,570	[2],[3]	$ 12,177	[2],[4]	2,608	[1],[2]	$ 1,587	[2],[5]	$ 5,204	[6],[7]	$ 261	[8]	$ (385)	[9]		21,942	5,080	1,365
Contingent consideration adjustment																		15,896	2,489	(630)
Property insurance recovery																		(5,363)
Other (income) expense, net-Gain from the sale of an equity investment																			(5,406)
Stock based compensation expense		$ 6,600																30,750	30,451	40,307
Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment							1,400
Building impairment and other expenses							4,200
Selling and Administrative
Segment Reporting Information [Line Items]
Stock based compensation expense																		18,139	18,024	26,486
Universal Robots
Segment Reporting Information [Line Items]
Contingent consideration adjustment			$ 5,400		$ 8,000				$ 1,200		5,339							15,300	5,300
Acquisition related costs																			1,000
Universal Robots | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment							800
Avionics Interface Technologies, LLC
Segment Reporting Information [Line Items]
Contingent consideration adjustment											$ (300)		$ (1,000)					600	(1,300)
Acquisition related costs																				400
Avionics Interface Technologies, LLC | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment							600
ZTEC Instruments, Inc.
Segment Reporting Information [Line Items]
Contingent consideration adjustment															$ (1,600)				(1,600)	(600)
System Test
Segment Reporting Information [Line Items]
Goodwill impairment charge																	$ 0
Cost of revenues-inventory charge																		630	8,324	2,125
Restructuring and other																		(49)	1,037	742
Corporate And Eliminations
Segment Reporting Information [Line Items]
Restructuring and other																				198
Total																		15,896	(1,813)	6,538
Corporate And Eliminations | Restructuring and other
Segment Reporting Information [Line Items]
Property insurance recovery																		(5,363)
Acquisition related costs																			1,104	372
Corporate And Eliminations | Other (income) expense, net
Segment Reporting Information [Line Items]
Other (income) expense, net-Gain from the sale of an equity investment																			(5,406)
Corporate And Eliminations | Selling and Administrative
Segment Reporting Information [Line Items]
Stock based compensation expense	[10]																			6,598
Corporate And Eliminations | Impairment of fixed assets and expenses related to the Japan earthquake | Restructuring and other
Segment Reporting Information [Line Items]
Building impairment and other expenses																		5,363
Corporate And Eliminations | Universal Robots | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment																		15,346	5,339
Corporate And Eliminations | Avionics Interface Technologies, LLC | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment																		550	(1,250)
Corporate And Eliminations | ZTEC Instruments, Inc. | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment																			(1,600)	(630)
Industrial Automation
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge	[11]																		1,567
Restructuring and other																		585
Wireless Test
Segment Reporting Information [Line Items]
Goodwill impairment charge							$ 254,946											254,946	(254,946)	98,897
Acquired intangible assets impairment charge																		83,339
Cost of revenues-inventory charge																		7,207	2,500	5,679
Restructuring and other																		2,650		565
Semiconductor Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge																		9,656	10,508	14,389
Restructuring and other																		$ 2,860	$ 499	$ 490

[1] Restructuring and other includes $4.2 million for an impairment of fixed assets, $0.9 million for expenses related to an earthquake in Kumamoto, Japan, and $1.4 million for the increase in the fair value of contingent consideration liability of which $0.8 million related to Universal Robots, and $0.6 million related to AIT, partially offset by $5.1 million of property insurance recovery related to the Japan earthquake.

[2] Teradyne recorded pension and post retirement net actuarial (gains) losses of $(1.2) million, $(0.7) million, $0.7 million and $(2.0) million for the first, second, third and fourth quarter in 2016, respectively. See Note B: "Accounting Policies" for a discussion of Teradyne's accounting policy.

[3] Restructuring and other includes a $5.4 million fair value adjustment to increase the Universal Robots acquisition contingent consideration.

[4] Restructuring and other includes an $8.0 million fair value adjustment to increase the Universal Robots acquisition contingent consideration.

[5] Restructuring and other includes a $1.2 million fair value adjustment to increase the Universal Robots acquisition contingent consideration.

[6] In the fourth quarter ended December 31, 2015, Teradyne recorded pension and post retirement net actuarial losses of $17.7 million. See Note B: "Accounting Policies" for a discussion of Teradyne's accounting policy.

[7] Restructuring and other includes a $5.3 million fair value adjustment to increase the Universal Robots acquisition contingent consideration, and a $(0.3) million fair value adjustment to decrease the AIT acquisition contingent consideration.

[8] Restructuring and other includes a $(1.0) million fair value adjustment to decrease the AIT acquisition contingent consideration.

[9] Restructuring and other includes a $(1.6) million fair value adjustment to decrease the ZTEC acquisition contingent consideration.

[10] Expense related to the January 2014 retirement of Teradyne's former chief executive officer; see Note O: "Stock-Based Compensation."

[11] Included in the cost of revenues for the year ended December 31, 2015 is the cost for purchase accounting inventory step-up.