XML 74 R51.htm IDEA: XBRL DOCUMENT v3.19.3
Components of Retirement Plan Costs (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Pension Plans        
Defined Benefit Plan Disclosure [Line Items]        
Service Cost $ 776 $ 848 $ 2,328 $ 2,544
Interest Cost 1,621 1,469 4,863 4,407
Expected Return on Plan Assets (2,119) (1,946) (6,356) (5,838)
Prior Service Cost Amortization 80 81 240 243
Actuarial Loss Amortization 1,081 1,447 3,243 4,341
Sub-total 1,439 1,899 4,318 5,697
Amounts Capitalized and Deferred (650) (962) (1,659) (2,590)
Net Periodic Benefit Cost Recognized 789 937 2,659 3,107
Other Postretirement Benefit Plans, Defined Benefit        
Defined Benefit Plan Disclosure [Line Items]        
Service Cost 576 733 1,728 2,199
Interest Cost 857 852 2,569 2,554
Expected Return on Plan Assets (412) (409) (1,234) (1,227)
Prior Service Cost Amortization 304 327 910 981
Actuarial Loss Amortization 56 346 170 1,038
Sub-total 1,381 1,849 4,143 5,545
Amounts Capitalized and Deferred (650) (930) (1,730) (2,557)
Net Periodic Benefit Cost Recognized 731 919 2,413 2,988
Supplemental Employee Retirement Plans, Defined Benefit        
Defined Benefit Plan Disclosure [Line Items]        
Service Cost 62 122 185 366
Interest Cost 142 101 426 303
Prior Service Cost Amortization 14 47 42 141
Actuarial Loss Amortization 157 121 471 365
Sub-total 375 391 1,124 1,175
Amounts Capitalized and Deferred (107) (113) (322) (339)
Net Periodic Benefit Cost Recognized $ 268 $ 278 $ 802 $ 836