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Condensed Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Statement of Comprehensive Income [Abstract] |  |  |  |
Amortization of prior service cost, tax | $ (5) | $ (5) | $ (15) | $ (15)
Net gain, tax | 28 | 10 | 83 | 95
Unrealized (loss)/gain on commodity contract cash flow hedges, tax | 282 | 152 | 935 | 496
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Interest Rate Swaps During Period, Tax | $ 10 | $ 0 | $ (4) | $ 0

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- Definition Amount of tax (expense) benefit of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580 + Details
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- Definition Amount of tax expense (benefit), before reclassification adjustments, related to increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580 + Details
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