Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2023
Goodwill [Line Items]
Goodwill	$ 1,165,761	$ 1,188,590	$ 1,178,218
Accumulated impairment losses	(762,566)	(762,566)	(762,566)
Foreign currency translation adjustment	12,457	(22,829)
Total Goodwill	403,195	426,024	415,652
Robotics
Goodwill [Line Items]
Goodwill	383,166	405,971	395,463
Foreign currency translation adjustment	12,297	(22,805)
Total Goodwill	383,166	405,971	395,463
Wireless Test
Goodwill [Line Items]
Goodwill	361,819	361,819	361,819
Accumulated impairment losses	(353,843)	(353,843)	(353,843)
Total Goodwill	7,976	7,976	7,976
Semiconductor Test
Goodwill [Line Items]
Goodwill	262,077	262,101	262,237
Accumulated impairment losses	(260,540)	(260,540)	(260,540)
Foreign currency translation adjustment	160	(24)
Total Goodwill	1,537	1,561	1,697
System Test
Goodwill [Line Items]
Goodwill	158,699	158,699	158,699
Accumulated impairment losses	(148,183)	(148,183)	(148,183)
Total Goodwill	$ 10,516	$ 10,516	$ 10,516