PENSION (Fair Value) (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	$ 1,050,509	$ 835,139
Cash And Cash Equivalents [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	16,710	22,457
EquitySecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	688,257	534,479
DebtSecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	341,140	273,979
Other Plan Assets
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	4,402	4,224
FairValueInputsLevel1Member
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	814,296	640,773
FairValueInputsLevel1Member | Cash And Cash Equivalents [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	1,376	2,010
FairValueInputsLevel1Member | EquitySecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	570,293	427,391
FairValueInputsLevel1Member | DebtSecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	242,627	211,372
FairValueInputsLevel2Member
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	231,811	190,142
FairValueInputsLevel2Member | Cash And Cash Equivalents [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	15,334	20,447
FairValueInputsLevel2Member | EquitySecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	117,964	107,088
FairValueInputsLevel2Member | DebtSecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	98,513	62,607
FairValueInputsLevel3Member
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	4,402	4,224	$ 10,721
FairValueInputsLevel3Member | Other Plan Assets
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	$ 4,402	$ 4,224