XML 106 R89.htm IDEA: XBRL DOCUMENT v3.3.1.900
Retirement Plans and Postretirement Medical Benefits (Effect of Change in the Assumed Health Care Cost Trend Rates) (Details) - Nonpension postretirement benefit plans
$ in Thousands
12 Months Ended
Dec. 31, 2015
USD ($)
Defined Benefit Plan Disclosure [Line Items]  
Effect of 1% increase on total of service and interest cost components $ 389
Effect of 1% decrease on total of service and interest cost components (326)
Effect of 1% increase on postretirement benefit obligation 7,841
Effect of 1% decrease on postretirement benefit obligation $ (6,730)