XML 66 R31.htm IDEA: XBRL DOCUMENT
v3.20.1

Employee and Retiree Benefit Plans (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2020
Retirement Benefits [Abstract] |
Components of Net Periodic Benefit Expense | The table that follows provides the components of net periodic benefit expense for the three-month periods ended March 31, 2020 and 2019.
| Three Months Ended March 31,
| Pension Benefits |  | Other Postretirement Benefits
(Thousands of dollars) | 2020 |  | 2019 |  | 2020 |  | 2019
Service cost | $ | 2,166 |  |  | 2,062 |  |  | 447 |  |  | 420 |
Interest cost | 5,791 |  |  | 7,151 |  |  | 794 |  |  | 945 |
Expected return on plan assets | (6,344 | ) |  | (6,460 | ) |  | — |  |  | — |
Amortization of prior service cost (credit) | 183 |  |  | 247 |  |  | — |  |  | (98 | )
Recognized actuarial loss | 4,269 |  |  | 3,514 |  |  | — |  |  | — |
Net periodic benefit expense | $ | 6,065 |  |  | 6,514 |  |  | 1,241 |  |  | 1,267 |

X
- References No definition available. + Details
Name: | us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration