Schedule of Segment Reporting Information by Segment Charges (Detail) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Oct. 04, 2015	Sep. 28, 2014	Mar. 30, 2014	Oct. 04, 2015	Sep. 28, 2014
Segment Reporting Information [Line Items]
Restructuring and other		$ 261	$ (405)		$ (124)	$ 167
Contingent consideration adjustment					(2,600)	(630)
Gain from the sale of an equity investment					(5,406)
Stock based compensation expense				$ 6,600
ZTEC Instruments, Inc.
Segment Reporting Information [Line Items]
Contingent consideration adjustment			(600)		(1,600)	(600)
Universal Robots
Segment Reporting Information [Line Items]
Acquisition related costs		100			1,100
Avionics Interface Technologies, LLC
Segment Reporting Information [Line Items]
Contingent consideration adjustment		(1,000)			(1,000)
Wireless Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge		901	1,267		2,077	5,239
Restructuring and other						426
Total		901	1,267		2,077	5,665
System Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge		460	763		8,225	1,944
Restructuring and other		923	225		923	371
Total		1,383	988		9,148	2,315
Industrial Automation
Segment Reporting Information [Line Items]
Cost of revenues-inventory step-up	[1]	972			1,567
Total		972			1,567
Semiconductor Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge		1,697	4,404		8,637	14,322
Restructuring and other		194			499
Total		1,891	4,404		9,136	14,322
Corporate And Eliminations
Segment Reporting Information [Line Items]
Total		(856)	(630)		(6,902)	5,968
Corporate And Eliminations | Other (income) expense, net
Segment Reporting Information [Line Items]
Gain from the sale of an equity investment					(5,406)
Corporate And Eliminations | Selling, General and Administrative Expenses
Segment Reporting Information [Line Items]
Stock based compensation expense	[2]					6,598
Corporate And Eliminations | ZTEC Instruments, Inc.
Segment Reporting Information [Line Items]
Contingent consideration adjustment					(1,600)
Corporate And Eliminations | ZTEC Instruments, Inc. | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment			$ (630)		(1,600)	$ (630)
Corporate And Eliminations | Universal Robots | Restructuring and other
Segment Reporting Information [Line Items]
Acquisition related costs		144			1,104
Corporate And Eliminations | Avionics Interface Technologies, LLC
Segment Reporting Information [Line Items]
Contingent consideration adjustment					(1,000)
Corporate And Eliminations | Avionics Interface Technologies, LLC | Restructuring and other
Segment Reporting Information [Line Items]
Contingent consideration adjustment		$ (1,000)			$ (1,000)

[1] Included in the cost of revenues for the three and nine months ended October 4, 2015 is the cost for purchase accounting inventory step-up.

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