v3.10.0.1
Employee Benefit Plans (Changes In Benefit Obligations And Plan Assets) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Pension Plan [Member]      
Change in benefit obligation:      
Benefit obligation at beginning of year $ 297,856 $ 225,970  
Service cost 38,167 20,497 $ 18,179
Interest cost 14,907 9,865 7,950
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant 0 0  
Actuarial loss (21,375) 59,686  
Benefits paid (14,356) (11,484)  
Settlements (6,250) (6,678)  
Benefit obligation at end of year 308,949 297,856 225,970
Change in plan assets:      
Beginning balance 198,686 166,906  
Employer contributions 31,717 26,533  
Plan participants’ contributions 0 0  
Actual return on plan assets (12,207) 23,409  
Defined Benefit Plan, Plan Assets, Benefits Paid 14,356 11,484  
Defined Benefit Plan, Plan Assets, Payment for Settlement (6,250) (6,678)  
Fair value of plan assets at end of year 197,590 198,686 166,906
Funded status at end of year (111,359) (99,170)  
Accumulated benefit obligation 208,840 206,480  
Other Postretirement Benefits [Member]      
Change in benefit obligation:      
Benefit obligation at beginning of year 12,760 13,011  
Service cost 243 243 235
Interest cost 416 475 489
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant 357 280  
Actuarial loss (599) (535)  
Benefits paid (1,097) (714)  
Settlements 0 0  
Benefit obligation at end of year 12,080 12,760 13,011
Change in plan assets:      
Beginning balance 0 0  
Employer contributions 740 434  
Plan participants’ contributions 357 280  
Actual return on plan assets 0 0  
Defined Benefit Plan, Plan Assets, Benefits Paid 1,097 714  
Defined Benefit Plan, Plan Assets, Payment for Settlement 0 0  
Fair value of plan assets at end of year 0 0 $ 0
Funded status at end of year $ (12,080) $ (12,760)