Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021
Goodwill [Line Items]
Foreign currency translation adjustment	$ (27,835)	$ 37,577
Goodwill	1,216,425	1,178,997	$ 1,188,590
Accumulated impairment losses		(762,566)	(762,566)
Goodwill	453,859	416,431	426,024
Autoguide LLC
Goodwill [Line Items]
Goodwill acquisition		(149)
Industrial Automation
Goodwill [Line Items]
Foreign currency translation adjustment	(27,781)	37,418
Goodwill	433,752	396,483	405,971
Goodwill	433,752	396,483	405,971
Industrial Automation | Autoguide LLC
Goodwill [Line Items]
Goodwill acquisition		(149)
Wireless Test
Goodwill [Line Items]
Goodwill	361,819	361,819	361,819
Accumulated impairment losses	(353,843)	(353,843)	(353,843)
Goodwill	7,976	7,976	7,976
Semiconductor Test
Goodwill [Line Items]
Foreign currency translation adjustment	(54)	159
Goodwill	262,155	261,996	262,101
Accumulated impairment losses	(260,540)	(260,540)	(260,540)
Goodwill	1,615	1,456	1,561
System Test
Goodwill [Line Items]
Goodwill	158,699	158,699	158,699
Accumulated impairment losses	(148,183)	(148,183)	(148,183)
Goodwill	$ 10,516	$ 10,516	$ 10,516