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PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Tables) | 3 Months Ended
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Mar. 31, 2017
PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS |
Summary of the components of net periodic benefit cost |
|  | Three Months Ended March 31 |
|  | Nonunion Defined |  | Supplemental |  | Postretirement |
|  | Benefit Pension Plan |  | Benefit Plan |  | Health Benefit Plan |
|  | 2017 |  | 2016 |  | 2017 |  | 2016 |  | 2017 |  | 2016 |
|  | (in thousands) |
Service cost |  | $ | — |  | $ | — |  | $ | — |  | $ | — |  | $ | 122 |  | $ | 107 |
Interest cost |  |  | 1,240 |  |  | 1,305 |  |  | 26 |  |  | 32 |  |  | 265 |  |  | 254 |
Expected return on plan assets |  |  | (2,167) |  |  | (1,946) |  |  | — |  |  | — |  |  | — |  |  | — |
Amortization of prior service credit |  |  | — |  |  | — |  |  | — |  |  | — |  |  | (47) |  |  | (47) |
Pension settlement expense |  |  | 1,957 |  |  | 900 |  |  | — |  |  | — |  |  | — |  |  | — |
Amortization of net actuarial loss(1) |  |  | 886 |  |  | 955 |  |  | 20 |  |  | 38 |  |  | 173 |  |  | 176 |
Net periodic benefit cost |  | $ | 1,916 |  | $ | 1,214 |  | $ | 46 |  | $ | 70 |  | $ | 513 |  | $ | 490 |
| (1) |  | The Company amortizes actuarial losses over the average remaining active service period of the plan participants and does not use a corridor approach.
Schedule of changes in the projected benefit obligation and plan assets of the nonunion defined benefit pension plan |
|  | Nonunion Defined
|  | Benefit Pension Plan
|  | (in thousands)
Change in benefit obligations |  |  |  |
Benefit obligations at December 31, 2016 |  | $ | 152,006 |
Interest cost |  |  | 1,240 |
Actuarial loss(1) |  |  | 4,290 |
Benefits paid |  |  | (12,532) |
Benefit obligations at March 31, 2017 |  |  | 145,004 |
Change in plan assets |  |  |  |
Fair value of plan assets at December 31, 2016 |  |  | 144,805 |
Actual return on plan assets |  |  | 4,050 |
Benefits paid |  |  | (12,532) |
Fair value of plan assets at March 31, 2017 |  |  | 136,323 |
Funded status at March 31, 2017(2) |  | $ | (8,681) |
Accumulated benefit obligation |  | $ | 145,004 |
| (1) |  | Primarily impacted by actuarial increases in the valuation of participant data as of January 1, 2017. The actuarial loss from remeasurement upon settlement was also impacted by a decrease in the discount rate at March 31, 2017 compared to the previous remeasurement at December 31, 2016.
| (2) |  | Noncurrent liability recognized within pension and postretirement liabilities in the accompanying consolidated balance sheet at March 31, 2017.

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- Definition Tabular disclosure of net funded status of pension plans and/or other employee benefit plans and disclosure of accumulated benefit obligation. + References No definition available. + Details
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- 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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 + Details
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