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ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Notes) | 12 Months Ended
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Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items] |
Comprehensive Income (Loss) Note [Text Block] |
6. | ACCUMULATED OTHER COMPREHENSIVE LOSS
The following table sets forth the balance in accumulated other comprehensive loss for the period indicated:
|  | Accumulated Other Comprehensive Loss
|  | (Thousands of dollars)
January 1, 2017 |  | $ | (4,715 | )
Pension and other postemployment benefit plans obligations |  |
Other comprehensive loss before reclassification, net of tax of $808 |  | (1,293 | )
Amounts reclassified from accumulated other comprehensive income, net of tax of $(322) |  | 515 |
Other comprehensive loss |  | (778 | )
December 31, 2017 |  | (5,493 | )
Pension and other postemployment benefit plans obligations |  |
Other comprehensive income before reclassification, net of tax of $(577) |  | 596 |
Amounts reclassified from accumulated other comprehensive loss, net of tax of $(271) |  | 811 |
Other comprehensive income |  | 1,407 |
December 31, 2018 |  | $ | (4,086 | )
The following table sets forth the effect of reclassifications from accumulated other comprehensive loss on our Consolidated Statements of Income for the period indicated:
|  |  |  |  |  |  | Affected Line Item in the
Details about Accumulated Other Comprehensive |  | Years Ended December 31, | Consolidated Statements of
Loss Components |  | 2018 |  | 2017 |  | 2016 | Income
|  | (Thousands of dollars) |
Pension and other postemployment benefit plan obligations (a) |  |  |  |  |  |  |
Amortization of net loss |  | $ | 43,800 |  |  | $ | 42,591 |  |  | $ | 40,912 |  |
Amortization of unrecognized prior service cost |  | (4,567 | ) |  | (4,597 | ) |  | (3,316 | ) |
|  | 39,233 |  |  | 37,994 |  |  | 37,596 |  |
Regulatory adjustments (b) |  | (38,151 | ) |  | (37,157 | ) |  | (36,845 | ) |
|  | 1,082 |  |  | 837 |  |  | 751 |  | Income before income taxes
|  | (271 | ) |  | (322 | ) |  | (289 | ) | Income tax expense
Total reclassifications for the period |  | $ | 811 |  |  | $ | 515 |  |  | $ | 462 |  | Net income
(a) These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note 12 for additional information regarding our net periodic benefit cost. (b) Regulatory adjustments represent pension and other postemployment benefit costs expected to be recovered through rates and are deferred as part of our regulatory assets. See Note 9 for additional information regarding our regulatory assets and liabilities.

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -URI http://asc.fasb.org/topic&trid=2134417 + Details
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