PENSION AND OTHER POST-RETIREMENT BENEFIT PLANS - SCHEDULE OF DEFINED BENEFIT OBLIGATIONS, PLAN ASSETS AND FUNDED STATUS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Amounts recognized in Accumulated Other Comprehensive Income (Loss), net of tax:
Net amounts recognized in AOCI	$ 194,205	$ 189,187
Pension Benefits
Change in benefit obligation
Projected benefit obligation at beginning of year	1,105,206	1,031,206
Service cost	21,734	20,878	$ 21,223
Interest cost	26,112	35,756	31,943
Actuarial loss	90,140	89,092
Settlement	(52,938)	(21,445)
Currency translation and other	1,822	2,956
Benefits paid	(23,238)	(53,237)
Projected benefit obligation at end of year	1,168,838	1,105,206	1,031,206
Change in plan assets
Fair value of plan assets at beginning of year	1,053,438	963,861
Actual return on plan assets	118,812	157,931
Employer contributions	2,862	3,660
Settlement	(52,938)	(21,445)
Currency translation and other	1,309	2,668
Benefits paid	(23,238)	(53,237)
Fair value of plan assets at end of year	1,100,245	1,053,438	963,861
Funded status at end of year	(68,593)	(51,768)
Amounts recognized in the Consolidated Balance Sheets:
Other assets	8,308	10,481
Accrued liabilities	(6,174)	(3,476)
Other long-term liabilities	(70,727)	(58,773)
Total	(68,593)	(51,768)
Amounts recognized in Accumulated Other Comprehensive Income (Loss), net of tax:
Actuarial net (loss) gain	(205,193)	(216,443)
Net prior service credit (cost)	21,706	27,031
Net amounts recognized in AOCI	(183,487)	(189,412)
Other Benefits
Change in benefit obligation
Projected benefit obligation at beginning of year	230,457	214,719
Service cost	159	151	230
Interest cost	6,029	7,837	6,923
Actuarial loss	15,218	23,635
Settlement	0	0
Currency translation and other	254	589
Benefits paid	(8,809)	(16,474)
Projected benefit obligation at end of year	243,308	230,457	214,719
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	8,809	16,474
Settlement	0	0
Currency translation and other	0	0
Benefits paid	(8,809)	(16,474)
Fair value of plan assets at end of year	0	0	$ 0
Funded status at end of year	(243,308)	(230,457)
Amounts recognized in the Consolidated Balance Sheets:
Other assets	0	0
Accrued liabilities	(19,801)	(19,251)
Other long-term liabilities	(223,507)	(211,206)
Total	(243,308)	(230,457)
Amounts recognized in Accumulated Other Comprehensive Income (Loss), net of tax:
Actuarial net (loss) gain	(10,718)	444
Net prior service credit (cost)	0	(219)
Net amounts recognized in AOCI	$ (10,718)	$ 225