Annual report pursuant to Section 13 and 15(d)

Postretirement Benefits, Schedule of Defined Benefit Plans Disclosure (Details)

v3.6.0.2
Postretirement Benefits, Schedule of Defined Benefit Plans Disclosure (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Change in projected benefit obligation:      
Benefit obligation at beginning of year $ 128,829 $ 129,053  
Service cost 3,806 3,985 $ 3,424
Interest cost 5,637 5,022 4,952
Actuarial (gain) loss 3,662 (5,959)  
Benefits paid (5,145) (3,272)  
Benefit obligation at end of year 136,789 128,829 129,053
Change in plan assets:      
Fair value of plan assets at beginning of year 86,828 84,893  
Actual gain (loss) on plan assets 6,779 (468)  
Employer contribution 1,181 5,675  
Benefits paid (5,145) (3,272)  
Fair value of plan assets at end of year 89,643 86,828 84,893
Reconciliation of funded status:      
Fair value of plan assets at end of year 89,643 86,828 84,893
Benefit obligation at end of year 136,789 128,829 $ 129,053
Under-funded status at end of year $ (47,146) $ (42,001)