XML 54 R43.htm IDEA: XBRL DOCUMENT v3.10.0.1
Defined Pension Plans (Narrative) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]        
Pension costs      
Pension period     30 years  
Defined Benefit Pension Plan [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Pension costs $ 1,049 $ 1,033 $ 3,147 3,070
Unfunded Supplemental Executive Retirement Plan [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Pension costs $ 255 $ 210 $ 766 $ 628