BENEFIT PLANS (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018 USD ($) employee ShareBasedCompensationPlan item	Dec. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of defined contribution plans | ShareBasedCompensationPlan		2
Expected return on plan assets		7.00%	7.00%
Contributions to multiemployer pension plans		$ 10,081	$ 9,253	$ 10,435
Percentage of contributions to individual multiemployer pension funds		5.00%	5.00%	5.00%
Percentage of domestic hourly labor force covered by collective bargaining agreements		8.50%
Percentage of domestic hourly labor force covered by collective bargaining agreements expiring in 2017		7.50%
Number of unfunded supplemental retirement plans | item		1	1
Accrued costs for supplemental retirement plan		$ 1,122	$ 1,252
Amount plan assets of Chemical Plan exceeds accumulated benefit obligation		6,525	5,346
Expense recognized related to defined contribution plans		$ 40,718	44,562	$ 45,295
Mexico [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of employees | employee		332
Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	5.75%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of funded, noncontributory defined benefit pension plans | ShareBasedCompensationPlan		3
Normal retirement age		65 years
Projected benefit obligation		$ 958,936	1,091,223	$ 1,006,674
Accumulated benefit obligation		958,899	$ 1,090,482
Estimated net actuarial loss expected to be amortized from accumulated other comprehensive income		4,933
Estimated prior service cost that will be amortized from accumulated other comprehensive income		$ 1,339
Expected return on plan assets		7.00%	7.00%	7.50%
Employer contributions		$ 109,631	$ 20,023	$ 9,576
Estimated employer contribution in 2019		$ 9,067
Discount rate		4.39%	3.72%	4.29%
Estimated weighted-average discount rate to measure service cost		3.90%	4.63%
Estimated weighted-average discount rate to measure interest cost		3.35%	3.63%
Pension Benefits [Member] | Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discretionary qualified plan contribution		$ 100,000	$ 10,600
Employer contributions				$ 0
Pension Benefits [Member] | Nonqualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of unfunded, nonqualified pension plans | ShareBasedCompensationPlan		3
Projected benefit obligation		$ 71,435	82,136
Accumulated benefit obligation		71,435	82,136
Employer contributions		9,631	$ 9,423	9,576
Estimated employer contribution in 2019		$ 9,067
Pension Benefits [Member] | Return Seeking [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation ranges for plan assets		70.00%	80.00%
Change to new asset allocation percent		55.00%
Pension Benefits [Member] | Liability Hedge [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation ranges for plan assets		30.00%	20.00%
Change to new asset allocation percent		45.00%
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Normal retirement age		65 years
Projected benefit obligation		$ 40,834	$ 43,480	$ 45,546
Estimated net actuarial loss expected to be amortized from accumulated other comprehensive income		(1,344)
Estimated prior service cost that will be amortized from accumulated other comprehensive income		(3,919)
Estimated employer contribution in 2019		$ 5,561
Discount rate		4.01%	3.33%	3.58%
Estimated weighted-average discount rate to measure service cost		3.56%	3.96%
Estimated weighted-average discount rate to measure interest cost		2.90%	2.89%
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		3.92%	3.24%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		4.47%	3.79%