Schedule of Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 28, 2014		Sep. 29, 2013		Sep. 28, 2014		Sep. 29, 2013
Segment Reporting Information [Line Items]
Net revenues	$ 478,010		$ 433,376		$ 1,324,587		$ 1,142,632
Income (loss) before income taxes	100,670	[1],[2]	87,552	[1],[2]	220,189	[1],[2]	166,483	[1],[2]
Semiconductor Test
Segment Reporting Information [Line Items]
Net revenues	380,083		304,131		1,063,254		808,068
Income (loss) before income taxes	91,900	[1],[2]	68,932	[1],[2]	233,770	[1],[2]	141,304	[1],[2]
Wireless Test
Segment Reporting Information [Line Items]
Net revenues	54,838		93,132		144,747		226,116
Income (loss) before income taxes	2,379	[1],[2]	27,575	[1],[2]	(8,477)	[1],[2]	41,491	[1],[2]
System Test
Segment Reporting Information [Line Items]
Net revenues	43,089		36,113		116,586		108,448
Income (loss) before income taxes	5,779	[1],[2]	(2,462)	[1],[2]	5,512	[1],[2]	(153)	[1],[2]
Corporate And Eliminations
Segment Reporting Information [Line Items]
Income (loss) before income taxes	$ 612	[1],[2]	$ (6,493)	[1],[2]	$ (10,616)	[1],[2]	$ (16,159)	[1],[2]

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

[2] Included in the income (loss) before income taxes for each of the segments are charges and credits for the three and nine months ended September 28, 2014 and September 29, 2013 that include restructuring and other, and provision for excess and obsolete inventory, as follows: