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Employee Benefit Plans (Defined Benefit Pension Plans not Recognized as Component of Combined Net Period Benefit Cost) (Detail) - Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items] |  |
Net actuarial loss | $ (64,343) | $ (57,964)
Deferred tax benefit | 13,512 | 12,210
Amounts included in accumulated other comprehensive loss, net of tax | $ (50,831) | $ (45,934)

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- Definition Amount, before tax, after reclassification adjustment, of increase (decrease) in accumulated other comprehensive income from gain (loss) 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 11 -URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e637-108580 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 (i) -URI http://asc.fasb.org/extlink&oid=121641772&loc=SL7669646-108580 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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- Definition Tax effect of plan amendments that occurred that has not been recognized in net periodic benefit cost. + 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=121641772&loc=d3e640-108580 + Details
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