Quarterly report pursuant to Section 13 or 15(d)

Supplemental Retirement Plan and Related Post Retirement Benefits - Summary of the Components of Net Periodic Cost (Details)

v3.10.0.1
Supplemental Retirement Plan and Related Post Retirement Benefits - Summary of the Components of Net Periodic Cost (Details)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 29, 2018
USD ($)
Sep. 30, 2017
USD ($)
Sep. 29, 2018
USD ($)
retirement_plan
Sep. 30, 2017
USD ($)
Retirement Benefits [Abstract]        
Number of non-qualified supplemental retirement defined benefit plans | retirement_plan     2  
SERP        
Defined Benefit Plan Disclosure        
Service Cost $ 50 $ 46 $ 150 $ 138
Interest Cost 225 224 675 672
Amortization of Prior Service Cost 97 97 291 291
Amortization of Net Actuarial Losses 157 93 471 279
Net Periodic Cost 529 460 1,587 1,380
SERP | SERP Medical        
Defined Benefit Plan Disclosure        
Service Cost 4 2 12 6
Interest Cost 11 10 34 30
Amortization of Prior Service Cost 4 4 12 12
Amortization of Net Actuarial Losses 15 7 44 21
Net Periodic Cost $ 34 $ 23 $ 102 $ 69