EMPLOYEE BENEFIT PLANS - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) employee	Dec. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of employees offered one-time distribution | employee		4,500
Number of employees who accepted one-time distribution | employee		1,700
Proportion of employees who accepted one-time distribution (as a percent)		38.00%
One-time distribution expense		$ 80,000
One-time distribution settlement		$ 90,000
Proportion of pension plan obligations settled (as a percent)		4.00%
Pension lump sum settlement expense related to unrecognized actuarial losses		$ 32,000
Accrued pension liability	$ 268,954	417,692
Expense related to defined contribution savings plans	40,000	39,000	$ 40,000
Deferred compensation liability	82,940	71,442
Non-qualified supplemental pension plan
Defined Benefit Plan Disclosure [Line Items]
Accrued pension liability	61,000	58,000
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plans	136,029	72,202
Prefunding contributions	98,000
Pension settlement expense	0	93,049
Reduction to projected benefit obligation	19,052	102,905
Net actuarial loss to be recognized	28,000
Benefit obligation	2,509,093	2,324,080	2,135,143
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	22,000	22,000
Company-administered plans: | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Curtailment loss	9,329	0	0
Rabbi Trusts | Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation liability	83,000	71,000
Deferred compensation assets	84,000	72,000
Rabbi trust investment income (loss)	$ 11,000	$ 11,000	$ (3,000)
United States
Defined Benefit Plan Disclosure [Line Items]
U.S. pension plan assets percentage of total pension plan assets	73.00%