Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Apr. 03, 2016	Dec. 31, 2015
Goodwill [Line Items]
Foreign currency translation adjustment	$ 7,458
Goodwill	1,003,491	$ 996,033
Accumulated impairment losses	(507,620)	(507,620)
Goodwill	495,871	488,413
Semiconductor Test
Goodwill [Line Items]
Goodwill	260,540	260,540
Accumulated impairment losses	(260,540)	(260,540)
Industrial Automation
Goodwill [Line Items]
Foreign currency translation adjustment	7,458
Goodwill	222,433	214,975
Goodwill	222,433	214,975
System Test
Goodwill [Line Items]
Goodwill	158,699	158,699
Accumulated impairment losses	(148,183)	(148,183)
Goodwill	10,516	10,516
Wireless Test
Goodwill [Line Items]
Goodwill	361,819	361,819
Accumulated impairment losses	(98,897)	(98,897)
Goodwill	$ 262,922	$ 262,922