Annual report pursuant to Section 13 and 15(d)

Retirement Plans and Related Post Retirement Benefits - Assumptions Used to Calculate the Post Retirement Benefit Obligation (Details)

v3.10.0.1
Retirement Plans and Related Post Retirement Benefits - Assumptions Used to Calculate the Post Retirement Benefit Obligation (Details)
Dec. 31, 2018
Dec. 31, 2017
SERP    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Discount Rate 4.20% 3.60%
Future Average Compensation Increases 2.00%  
SERP Medical    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Discount Rate 4.20% 3.60%
Minimum | SERP    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Future Average Compensation Increases 2.00% 2.00%
Maximum | SERP    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Future Average Compensation Increases 3.00%