EMPLOYEE BENEFIT PLANS - Expected Benefit Payments, Net (Details) - Other Benefits $ in Thousands	Dec. 31, 2020 USD ($)
Expected Benefit Payments Before Medicare Part D Subsidy
2021	$ 3,462
2022	3,775
2023	4,140
2024	4,619
2025	4,896
2026-2030	28,681
Total payments	49,573
Effect of Medicare Part D Subsidy on Expected Benefit Payments
2021	(303)
2022	(337)
2023	(369)
2024	(399)
2025	(439)
2026-2030	(2,796)
Total payments	(4,643)
Expected Benefit Payments Net of Medicare Part D Subsidy
2021	3,159
2022	3,438
2023	3,771
2024	4,220
2025	4,457
2026-2030	25,885
Total payments	$ 44,930

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