EMPLOYEE BENEFIT PLANS Benefit Obligations, Plan Assets, and Funded Status (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Defined Benefit Plan Disclosure
Defined Benefit Plan, Benefit Obligation		$ 819,339	$ 134,852	[1]	$ 105,515	[1]
Defined Benefit Plan, Benefit Obligation, Business Combination	[2]	619,099	0	[1]
Service Cost		10,792	4,602	[1]	5,242
Interest cost		11,949	4,362	[1]	4,137
Participant contributions		728	736	[1]
Actuarial (gain) loss		26,955	18,591	[1]
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(13,230)	(4,459)	[1]
DefinedBenefitPlanBenefitsPaidFromCompanyAssets		(995)	0	[1]
Curtailment		(101)	0	[1]
Plan Amendment		(37)	0	[1]
Settlement		(1,235)	0	[1]
Foreign Currency Translation Gain (Loss)		30,562	5,505	[1]
Defined Benefit Plan, Plan Assets, Amount		721,005	103,385	[1]	86,556	[1]
Defined Benefit Plan, Plan Assets, Business Combination	[2]	542,936	0	[1]
Actual return on plan assets		59,164	12,763	[1]
Participant contributi		728	736	[1]
Company contributions		6,838	3,198	[1]
Defined Benefit Plan, Plan Assets, Benefits Paid		(13,230)	(4,459)	[1]
Settlement		(1,235)	0	[1]
Foreign Currency Translation Gain (Loss)		22,419	4,591	[1]
Funded status		(98,334)	(31,467)	[1]
Assets for Plan Benefits, Defined Benefit Plan		41,100	0	[1]
Current liabilities		(18,589)	(383)	[1]
Non-current liabilities		$ (120,845)	$ (31,084)	[1]
Discount rate		2.20%	3.20%	[1]
Average salary increases		3.40%	3.50%	[1]
United States
Defined Benefit Plan Disclosure
Defined Benefit Plan, Benefit Obligation		$ 332,484	$ 0		0
Defined Benefit Plan, Benefit Obligation, Business Combination	[2]	317,893	0
Service Cost		1,763	0		0
Interest cost		4,787	0		0
Participant contributions		0	0
Actuarial (gain) loss		12,911	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(4,222)	0
DefinedBenefitPlanBenefitsPaidFromCompanyAssets		(547)	0
Curtailment		(101)	0
Plan Amendment		0	0
Settlement		0	0
Foreign Currency Translation Gain (Loss)		0	0
Defined Benefit Plan, Plan Assets, Amount		355,287	0		0
Defined Benefit Plan, Plan Assets, Business Combination	[2]	324,292	0
Actual return on plan assets		35,217	0
Participant contributi		0	0
Company contributions		0	0
Defined Benefit Plan, Plan Assets, Benefits Paid		(4,222)	0
Settlement		0	0
Foreign Currency Translation Gain (Loss)		0	0
Funded status		22,803	0
Assets for Plan Benefits, Defined Benefit Plan		40,921	0
Current liabilities		(18,118)	0
Non-current liabilities		$ 0	$ 0
Discount rate		2.60%	0.00%
Average salary increases		3.80%	0.00%
Foreign Plan [Member]
Defined Benefit Plan Disclosure
Defined Benefit Plan, Benefit Obligation		$ 486,855	$ 134,852	[1]	105,515	[1]
Defined Benefit Plan, Benefit Obligation, Business Combination	[2]	301,206	0	[1]
Service Cost		9,029	4,602	[1]	5,242
Interest cost		7,162	4,362	[1]	4,137
Participant contributions		728	736	[1]
Actuarial (gain) loss		14,044	18,591	[1]
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(9,008)	(4,459)	[1]
DefinedBenefitPlanBenefitsPaidFromCompanyAssets		(448)	0	[1]
Curtailment		0	0	[1]
Plan Amendment		(37)	0	[1]
Settlement		(1,235)	0	[1]
Foreign Currency Translation Gain (Loss)		30,562	5,505	[1]
Defined Benefit Plan, Plan Assets, Amount		365,718	103,385	[1]	$ 86,556	[1]
Defined Benefit Plan, Plan Assets, Business Combination	[2]	218,644	0	[1]
Actual return on plan assets		23,947	12,763	[1]
Participant contributi		728	736	[1]
Company contributions		6,838	3,198	[1]
Defined Benefit Plan, Plan Assets, Benefits Paid		(9,008)	(4,459)	[1]
Settlement		(1,235)	0	[1]
Foreign Currency Translation Gain (Loss)		22,419	4,591	[1]
Funded status		(121,137)	(31,467)	[1]
Assets for Plan Benefits, Defined Benefit Plan		179	0	[1]
Current liabilities		(471)	(383)	[1]
Non-current liabilities		$ (120,845)	$ (31,084)	[1]
Discount rate		2.00%	3.20%	[1]
Average salary increases		3.20%	3.50%	[1]

[1] For 2019, the changes in benefit obligations, plan assets and funded status relate to the EECOL Plan and the EECOL SERP

[2] As described above, the Company assumed the Domestic Plans and certain foreign plans in connection with the June 22, 2020 acquisition of Anixter.