PENSION (Fair Value) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	$ 776,482	$ 714,608
Cash And Cash Equivalents [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	42,374	23,979
EquitySecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	504,633	459,002
DebtSecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	216,372	219,249
Alternative Investments [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	10,912	10,760
Other Assets [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	2,191	1,618
FairValueInputsLevel1Member
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	617,991	578,403
FairValueInputsLevel1Member | Cash And Cash Equivalents [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	12,551	4,893
FairValueInputsLevel1Member | EquitySecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	455,175	418,390
FairValueInputsLevel1Member | DebtSecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	150,265	155,120
FairValueInputsLevel2Member
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	145,388	123,827
FairValueInputsLevel2Member | Cash And Cash Equivalents [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	29,823	19,086
FairValueInputsLevel2Member | EquitySecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	49,458	40,612
FairValueInputsLevel2Member | DebtSecuritiesMember
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	66,107	64,129
FairValueInputsLevel3Member
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	13,103	12,378	$ 10,475
FairValueInputsLevel3Member | Alternative Investments [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	10,912	10,760
FairValueInputsLevel3Member | Insurance Contracts [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	10,912	10,760	9,720
FairValueInputsLevel3Member | Other Assets [Member]
Defined Benefit Plan Fair Value Disclosure [Line Items]
DefinedBenefitPlanFairValueOfPlanAssets	$ 2,191	$ 1,618	$ 755