Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation (Details)

v3.19.1
Basis of Presentation (Details)
$ in Thousands
3 Months Ended
Feb. 13, 2019
USD ($)
Oct. 12, 2018
Mar. 30, 2019
USD ($)
Mar. 31, 2018
USD ($)
Jan. 01, 2019
USD ($)
Dec. 31, 2018
USD ($)
Business Acquisition [Line Items]            
Research and development, design and related engineering     $ 26,700 $ 28,900    
Adoption of ASU 2018-02       $ 1,400    
Right-of-use assets     22,900      
Lease liability     23,116      
Property, plant and equipment, net     (117,307)     $ (120,862)
Accounting Standards Update 2016-02            
Business Acquisition [Line Items]            
Right-of-use assets         $ 18,400  
Lease liability         18,500  
Accounting Standards Update 2016-02 | Reclassification            
Business Acquisition [Line Items]            
Property, plant and equipment, net         $ 3,500  
Convertible Class B Stock            
Business Acquisition [Line Items]            
Stock split ratio, common stock   0.15        
Divestiture by Sale | Test Systems Segment            
Business Acquisition [Line Items]            
Total cash proceeds of divesture $ 103,800          
Gain on sale, net of tax     80,100      
Income taxes from divesture     $ 21,300