EMPLOYEE BENEFIT PLANS - Qualified Pension Plan Funding Policy (Details) - Qualified Plan - Qualified Pension Plan	12 Months Ended
	Dec. 31, 2019 USD ($)
EMPLOYEE BENEFIT PLANS
Adjusted funding target attainment percentage	80.00%
Contribution to defined benefit pension plan for prior year	$ 17,400,000
Minimum
EMPLOYEE BENEFIT PLANS
Estimated future contribution to defined benefit pension plan	10,000,000
Maximum
EMPLOYEE BENEFIT PLANS
Estimated future contribution to defined benefit pension plan	$ 25,000,000