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)

v3.7.0.1
Supplemental Retirement Plan and Related Post Retirement Benefits - Summary of the Components of Net Periodic Cost (Details)
$ in Thousands
3 Months Ended 6 Months Ended
Jul. 01, 2017
USD ($)
Jul. 02, 2016
USD ($)
Jul. 01, 2017
USD ($)
retirement_plan
Jul. 02, 2016
USD ($)
Retirement Benefits [Abstract]        
Number of non-qualified supplemental retirement defined benefit plans | retirement_plan     2  
SERP        
Defined Benefit Plan Disclosure        
Service Cost $ 46 $ 43 $ 92 $ 86
Interest Cost 224 225 448 450
Amortization of Prior Service Cost 97 103 194 207
Amortization of Net Actuarial Losses 93 86 186 172
Net Periodic Cost 460 457 920 915
SERP | SERP Medical        
Defined Benefit Plan Disclosure        
Service Cost 2 1 4 2
Interest Cost 10 10 20 20
Amortization of Prior Service Cost 5 6 8 12
Amortization of Net Actuarial Losses 6 6 15 11
Net Periodic Cost $ 23 $ 23 $ 47 $ 45