EMPLOYEE BENEFIT PLANS - Pension Expense From Continuing Operations (Details) - Pension Plans - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Company-administered plans:
Service cost	$ 11,915	$ 11,007
Interest cost	67,781	84,960
Amortization of:
Postretirement benefit income	34,263	81,908	$ 29,892
Company-administered plans:
Company-administered plans:
Service cost	11,915	11,007	12,108
Interest cost	67,781	84,960	78,234
Expected return on plan assets	(97,526)	(91,034)	(101,980)
Pension settlement expense	0	34,974	3,061
Curtailment loss	9,329	0	0
Amortization of:
Net actuarial loss	31,134	30,708	28,593
Prior service cost	653	711	550
Postretirement benefit income	23,286	71,326	20,566
Company-administered plans: | United States
Amortization of:
Postretirement benefit income	32,503	75,936	28,043
Company-administered plans: | Foreign
Amortization of:
Postretirement benefit income	(9,217)	(4,610)	(7,477)
Multi-employer plans
Amortization of:
Postretirement benefit income	$ 10,977	$ 10,582	$ 9,326