Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
Apr. 02, 2017	Dec. 31, 2016
Goodwill [Line Items]
Foreign currency translation adjustment	$ 6,722
Goodwill	992,631	$ 985,909
Accumulated impairment losses	(762,566)	(762,566)
Goodwill	230,065	223,343
Wireless Test
Goodwill [Line Items]
Goodwill	361,819	361,819
Accumulated impairment losses	(353,843)	(353,843)
Goodwill	7,976	7,976
Industrial Automation
Goodwill [Line Items]
Foreign currency translation adjustment	6,722
Goodwill	211,573	204,851
Goodwill	211,573	204,851
System Test
Goodwill [Line Items]
Goodwill	158,699	158,699
Accumulated impairment losses	(148,183)	(148,183)
Goodwill	10,516	10,516
Semiconductor Test
Goodwill [Line Items]
Goodwill	260,540	260,540
Accumulated impairment losses	$ (260,540)	$ (260,540)

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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