XML 78 R61.htm IDEA: XBRL DOCUMENT v3.8.0.1
Benefit Plans Amounts Recognized in Balance Sheet (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]    
Noncurrent liabilities $ 72,841 $ 70,177
Pension Plan [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Current liabilities 1,099 1,032
Noncurrent liabilities 61,748 59,170
Liabilities 62,847 60,202
Other Postretirement Benefits Plan [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Current liabilities 86 87
Noncurrent liabilities 11,113 11,008
Liabilities $ 11,199 $ 11,095