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EMPLOYEE BENEFIT PLANS - Settlement distributions and expense (Details) - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Distributions and pension settlement expense |  |
Pension settlement expense, pre-tax | $ 89 | $ 8,505
Nonunion Defined Benefit Pension Plan |  |
Distributions and pension settlement expense |  |
Pension settlement distributions |  | 33,938
Pension settlement expense, pre-tax |  | $ 4,164
Pension settlement expense per diluted share, net of taxes |  | $ 0.12
Lump-sum distributions |  | $ 18,400
Nonparticipating annuity contract purchase price |  | 14,000
Transfer of remaining obligation to PGBC |  | 1,500
Noncash charge to pension settlement expense |  | 4,000
Supplemental Benefit Plan |  |
Distributions and pension settlement expense |  |
Pension settlement distributions | 2,887 | 937
Pension settlement expense, pre-tax | $ 89 | $ 370
Pension settlement expense per diluted share, net of taxes |  | $ 0.01
Period of delay for pension settlement distribution to key employees | 6 months | 6 months

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- Definition Amount of decrease in benefit obligation of defined benefit plan for transfer of benefit obligation to PBGC, which is an irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. + References No definition available. + Details
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- Definition -- None. No documentation exists for this element. -- + References No definition available. + Details
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- Definition The amount of lump sum benefit distributions paid. + References No definition available. + Details
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- Definition Represents the period of delay provision for key employees as required by Section 409A of the Internal Revenue Code related to lump-sum termination payment. + References No definition available. + Details
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- Definition The amount of net gain (loss), per diluted share, net of taxes, recognized in net periodic benefit cost as a result of an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. + References No definition available. + Details
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- Definition Amount paid for nonparticipating annuity contract to settle vested benefit obligations of participants and beneficiaries receiving monthly benefits. + References No definition available. + Details
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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(7) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 3A -URI http://asc.fasb.org/extlink&oid=123453770&loc=SL108413299-114919 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(7) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e2709-114920 + Details
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- Definition Amount of payment, which decreases plan assets of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(8) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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- Definition Amount of noncash expense (reversal of expense) for pension benefits. Excludes other postretirement benefits. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585 + Details
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- Details
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