Annual report pursuant to Section 13 and 15(d)

Retirement Plans and Related Post Retirement Benefits - Summarizes the Components of the Net Periodic Cost (Details)

v3.10.0.1
Retirement Plans and Related Post Retirement Benefits - Summarizes the Components of the Net Periodic Cost (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
SERP      
Net Periodic Cost      
Service Cost — Benefits Earned During Period $ 200 $ 186 $ 173
Interest Cost 899 897 901
Amortization of Prior Service Cost 386 387 413
Amortization of Losses 629 369 343
Net Periodic Cost 2,114 1,839 1,830
SERP Medical      
Net Periodic Cost      
Service Cost — Benefits Earned During Period 16 7 5
Interest Cost 46 41 40
Amortization of Prior Service Cost 16 16 24
Amortization of Losses 59 31 22
Net Periodic Cost $ 137 $ 95 $ 91