XML 88 R67.htm IDEA: XBRL DOCUMENT v3.10.0.1
Property, Plant and Equipment - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Property, Plant and Equipment [Line Items]      
Depreciation of property, plant and equipment $ 67,415 $ 66,122 $ 64,782
Machinery and equipment 689,770 647,961  
Accumulated depreciation 681,641 646,045  
Test Systems Leased By Customers      
Property, Plant and Equipment [Line Items]      
Machinery and equipment 5,500 18,100  
Accumulated depreciation $ 5,200 $ 13,700