Schedule of Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Oct. 02, 2011		Sep. 30, 2012		Oct. 02, 2011
Segment Reporting Information
Net revenues	$ 463,394		$ 344,389		$ 1,408,346		$ 1,132,069
Income (loss) from continuing operations before income taxes	103,025	[1],[2]	58,465	[1],[2]	296,261	[1],[2]	229,812	[1],[2]
Semiconductor Test
Segment Reporting Information
Net revenues	310,979		241,394		943,625		903,740
Income (loss) from continuing operations before income taxes	55,348	[1],[2]	37,244	[1],[2]	181,594	[1],[2]	205,144	[1],[2]
Systems Test Group
Segment Reporting Information
Net revenues	33,844		102,995		202,894		228,329
Income (loss) from continuing operations before income taxes	(2,642)	[1],[2]	25,563	[1],[2]	30,964	[1],[2]	39,877	[1],[2]
Wireless Test
Segment Reporting Information
Net revenues	118,571				261,827
Income (loss) from continuing operations before income taxes	58,902	[1],[2]			97,729	[1],[2]
Corporate And Eliminations
Segment Reporting Information
Income (loss) from continuing operations before income taxes	$ (8,583)	[1],[2]	$ (4,342)	[1],[2]	$ (14,026)	[1],[2]	$ (15,209)	[1],[2]

[1] Pension and post retirement actuarial gains and losses, interest income, and interest expense and other are included in Corporate and Eliminations.

[2] Included in the income (loss) from continuing operations before income taxes for each of the segments are charges and credits for the three and nine months ended September 30, 2012 and October 2, 2011 that include restructuring and other, net, and provision for excess and obsolete inventory, as follows: