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Property, Plant and Equipment - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Property, Plant and Equipment [Line Items]      
Depreciation of property, plant and equipment $ 80,119 $ 70,834 $ 67,415
Machinery and equipment 956,035 834,970  
Accumulated depreciation 789,524 729,669  
Test Systems Leased By Customers      
Property, Plant and Equipment [Line Items]      
Machinery and equipment 23,400 5,400  
Accumulated depreciation $ 7,500 $ 5,100