Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Equity - Components of Accumulated Other Comprehensive Income (Loss) (Details)

v3.19.1
Shareholders' Equity - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Thousands
Mar. 30, 2019
Dec. 31, 2018
Mar. 31, 2018
Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Total Shareholders’ Equity $ 466,003 $ 386,625 $ 338,028  
Foreign Currency Translation Adjustments        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Total Shareholders’ Equity (7,426) (7,156)    
Retirement Liability Adjustment        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Retirement Liability Adjustment – Before Tax (7,628) (7,814)    
Tax Benefit of Retirement Liability Adjustment 1,605 1,641    
Total Shareholders’ Equity (6,023) (6,173)    
ACCUMULATED OTHER COMPREHENSIVE LOSS        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Total Shareholders’ Equity $ (13,449) $ (13,329) $ (14,277) $ (13,352)