XML 107 R93.htm IDEA: XBRL DOCUMENT v3.8.0.1
Employee Benefit Plans Plans with Benefit Obligations in Excess of Assets Table (Details) - Pension Plans, Defined Benefit [Member] - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Accumulated Benefit Obligation $ (36,720) $ (34,790)  
Defined Benefit Plan, Benefit Obligation (39,030) (37,640) $ (38,240)
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation (18,420) (17,400)  
Defined Benefit Plan, Plan with Benefit Obligation in Excess of Plan Assets, Benefit Obligation (18,440) (37,200)  
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Fair Value of Plan Assets 9,980 7,880  
Defined Benefit Plan, Plan with Benefit Obligation in Excess of Plan Assets, Fair Value of Plan Assets $ 9,980 $ 25,080