SENTAL Acquisition - Business Acquisition (Details) - USD ($)
$ in Thousands
3 Months Ended
Jan. 23, 2018
Mar. 29, 2019
Mar. 30, 2018
Dec. 31, 2018
Business Acquisition [Line Items]        
Goodwill   $ 233,619   $ 233,619
Price, net of cash acquired   $ 0 $ 37,210  
SENTEL        
Business Acquisition [Line Items]        
Receivables $ 23,339      
Property, plant and equipment 810      
Goodwill 16,689      
Intangible assets 10,500      
Other current assets 975      
Accounts payable (10,012)      
Other current liabilities (5,446)      
Price, net of cash acquired $ 36,855