Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Equity - Summary of Changes in Shareholders' Equity (Details)

v3.10.0.1
Shareholders' Equity - Summary of Changes in Shareholders' Equity (Details)
$ / shares in Units, shares in Thousands
 3 Months Ended 9 Months Ended 25 Months Ended
Oct. 12, 2018
Dec. 12, 2017
USD ($)
Sep. 29, 2018
USD ($)
$ / shares
shares
Mar. 31, 2018
USD ($)
shares
Sep. 30, 2017
USD ($)
Sep. 29, 2018
USD ($)
$ / shares
shares
Sep. 30, 2017
USD ($)
Mar. 31, 2018
shares
Jan. 01, 2018
USD ($)
Dec. 31, 2017
USD ($)
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Beginning of Period       $ 329,927,000   $ 329,927,000        
Adoption of ASU 2018-02       1,400,000            
Foreign Currency Translation Adjustment     $ 226,000   $ 1,496,000 (1,346,000) $ 3,987,000      
Retirement Liability Adjustment – Net of Tax     216,000   130,000 646,000 392,000      
Net Income     16,999,000   $ 6,060,000 34,318,000 $ 25,332,000      
End of Period     $ 369,445,000     $ 369,445,000        
Common Stock                    
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
End of Period (in shares) | shares     21,654     21,654        
Convertible Class B Stock                    
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
End of Period (in shares) | shares     10,661     10,661        
Convertible Class B Stock | Subsequent Event                    
Class of Stock [Line Items]                    
Stock split ratio, common stock 0.15                  
COMMON STOCK                    
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Beginning of Period       $ 340,000   $ 340,000        
Conversion of Class B Shares to Common Shares                  
Exercise of Stock Options           1,000        
End of Period     $ 341,000     $ 341,000        
COMMON STOCK | Common Stock                    
Class of Stock [Line Items]                    
Shares Authorized (in shares) | shares     40,000     40,000        
Share Par Value (in usd per share) | $ / shares     $ 0.01     $ 0.01        
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Beginning of Period (in shares) | shares       22,861   22,861        
Conversion of Class B Shares to Common Shares (in shares) | shares           443        
Exercise of Stock Options (in shares) | shares           25        
End of Period (in shares) | shares     23,329     23,329        
COMMON STOCK | Convertible Class B Stock                    
Class of Stock [Line Items]                    
Shares Authorized (in shares) | shares     15,000     15,000        
Share Par Value (in usd per share) | $ / shares     $ 0.01     $ 0.01        
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Beginning of Period (in shares) | shares       11,082   11,082        
Conversion of Class B Shares to Common Shares (in shares) | shares           (443)        
Exercise of Stock Options (in shares) | shares           22        
End of Period (in shares) | shares     10,661     10,661        
ADDITIONAL PAID IN CAPITAL                    
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Beginning of Period       $ 67,748,000   $ 67,748,000        
Exercise of Stock Options           282,000        
Stock Compensation Expense           2,349,000        
End of Period     $ 70,379,000     70,379,000        
ACCUMULATED OTHER COMPREHENSIVE LOSS                    
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Beginning of Period       (13,352,000)   (13,352,000)        
Adoption of ASU 2018-02           (1,373,000)        
Foreign Currency Translation Adjustment           (1,346,000)        
Retirement Liability Adjustment – Net of Tax           646,000        
End of Period     (15,425,000)     (15,425,000)        
RETAINED EARNINGS                    
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Beginning of Period       325,191,000   325,191,000        
Adoption of ASU 2018-02           1,373,000        
Net Income           34,318,000        
End of Period     364,150,000     364,150,000        
RETAINED EARNINGS | Accounting Standards Update 2014-09                    
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Adoption of ASU 2014-09                 $ 3,300,000 $ 3,268,000
TREASURY STOCK                    
Increase (Decrease) in Stockholders' Equity [Roll Forward]                    
Beginning of Period       $ (50,000,000)   $ (50,000,000)        
Beginning of Period (in shares) | shares       (1,675)   (1,675)        
Purchase   $ (50,000,000)       $ 0        
Purchase (in shares) | shares           0   1,675    
End of Period     $ (50,000,000)     $ (50,000,000)        
End of Period (in shares) | shares     (1,675)     (1,675)