PENSION AND OTHER POST-RETIREMENT BENEFIT PLANS - PENSION AND OTHER POST-RETIREMENT BENEFIT PLANS NARRATIVE (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) postretirement_plan	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2025	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Number of Defined Benefit Other Post-retirement Plans and Defined Contribution Other Post-retirement Plans | postretirement_plan	2
Defined Benefit Plan, Accumulated Benefit Obligation	$ 1,063,955	$ 994,278
Defined Contribution Plan, Cost	47,651	47,959	$ 46,154
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ (89,092)	$ 50,432
Discount rate	3.10%	4.10%
Employer contributions	$ 3,660	$ 9,233
Defined Benefit Plans, Minimum Future Employer Contributions in Next Fiscal Year	1,503
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ (23,635)	$ 10,842
Discount rate	3.20%	4.20%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	6.40%	7.00%
Employer contributions	$ 16,474	$ 16,631
Other Benefits | Scenario, Forecast
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate				5.00%	5.00%