Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation (Details)

v3.10.0.1
Basis of Presentation (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2018
Mar. 31, 2018
Jul. 01, 2017
Jun. 30, 2018
Jul. 01, 2017
Jan. 01, 2018
Dec. 31, 2017
Business Acquisition [Line Items]              
Research and development, design and related engineering $ 28,900   $ 23,000 $ 57,800 $ 45,800    
Capitalized precontract cost 9,500     9,500      
Adoption of ASU 2018-02   $ 1,400          
ACCUMULATED OTHER COMPREHENSIVE LOSS              
Business Acquisition [Line Items]              
Adoption of ASU 2018-02       (1,373)      
RETAINED EARNINGS              
Business Acquisition [Line Items]              
Adoption of ASU 2018-02       1,373      
Accounting Standards Update 2014-09 | RETAINED EARNINGS              
Business Acquisition [Line Items]              
Adoption of ASU 2014-09           $ 3,300 $ 3,268
Selling, General and Administrative Expenses | Accounting Standards Update 2017-07              
Business Acquisition [Line Items]              
Other net periodic benefit costs 500   400 1,000 900    
Other Expense | Accounting Standards Update 2017-07              
Business Acquisition [Line Items]              
Other net periodic benefit costs $ (500)   $ (400) $ (1,000) $ (900)