SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020 USD ($)		Jun. 30, 2019 USD ($)		Jun. 30, 2020 USD ($) segment		Jun. 30, 2019 USD ($)
Financial information for the reportable segments
Rationalization and asset impairment charges (Note 6)	$ 23,238		$ 1,307		$ 29,759		$ 4,842
Number of operating segments | segment					3
Net sales	590,727		777,008		$ 1,292,718		1,536,182
Inter-segment sales	0		0		0		0
Total	590,727		777,008		1,292,718		1,536,182
EBIT, as adjusted	66,133		109,548		154,843		212,114
Special items charge (gain)	26,572	[1]	166	[2]	33,899	[1]	4,491	[2]
EBIT	39,561		109,382		120,944		207,623
Interest income	424		592		1,284		1,556
Interest expense	(6,305)		(6,490)		(12,623)		(12,777)
Income before income taxes	33,680		103,484		109,605		196,402
The Harris Products Group
Financial information for the reportable segments
Net sales	80,331		88,095		165,864		171,464
Inter-segment sales	1,753		2,113		3,478		3,980
Total	82,084		90,208		169,342		175,444
EBIT, as adjusted	11,713		13,488		24,205		24,007
Special items charge (gain)	0	[1]	0	[2]	0	[1]	0	[2]
EBIT	11,713		13,488		24,205		24,007
Corporate / Eliminations
Financial information for the reportable segments
Acquisition Transaction and Integration Costs			1,014				1,804
Net sales	0		0		0		0
Inter-segment sales	(33,532)		(41,112)		(64,523)		(76,576)
Total	(33,532)		(41,112)		(64,523)		(76,576)
EBIT, as adjusted	(1,964)		(3,969)		(3,063)		(7,011)
Special items charge (gain)	0	[1]	1,014	[2]	0	[1]	1,804	[2]
EBIT	(1,964)		(4,983)		(3,063)		(8,815)
Americas Welding
Financial information for the reportable segments
Rationalization and asset impairment charges (Note 6)	22,673		380		23,863		1,716
Net sales	333,229		476,607		751,764		934,326
Inter-segment sales	27,493		34,811		52,276		64,199
Total	360,722		511,418		804,040		998,525
EBIT, as adjusted	46,702		84,851		117,404		166,603
Special items charge (gain)	26,007	[1]	1,779	[2]	27,197	[1]	3,115	[2]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Gain (Loss) Due to Settlement and Curtailment	(3,334)				(3,334)
Business Combination, Inventory Step Up			1,399				1,399
EBIT	20,695		83,072		90,207		163,488
International Welding
Financial information for the reportable segments
Rationalization and asset impairment charges (Note 6)	565		927		5,896		3,126
Net sales	177,167		212,306		375,090		430,392
Inter-segment sales	4,286		4,188		8,769		8,397
Total	181,453		216,494		383,859		438,789
EBIT, as adjusted	9,682		15,178		16,297		28,515
Special items charge (gain)	565	[1]	(2,627)	[2]	6,702	[1]	(428)	[2]
Business Combination, Inventory Step Up					806
Gain (Loss) on Disposition of Assets			3,554				3,554
EBIT	$ 9,117		$ 17,805		$ 9,595		$ 28,943

[1] In the three months ended June 30, 2020, special items reflect Rationalization and asset impairment charges of $22,673 and $565 in Americas Welding and International Welding, respectively, and pension settlement charges of $3,334 in Americas Welding. In the six months ended June 30, 2020, special items reflect Rationalization and asset impairment charges of $23,863 and $5,896 in Americas Welding and International Welding, respectively, amortization of step up in value of acquired inventories of $806 related to an acquisition in International Welding and pension settlement charges of $3,334 in Americas Welding.

[2] In the three months ended June 30, 2019, special items reflect Rationalization and asset impairment charges of $380 in Americas Welding and $927 in International Welding, amortization of step up in value of acquired inventories of $1,399 in Americas Welding, gains on disposal of assets of $3,554 in International Welding and transaction and integration costs of $1,014 in Corporate / Eliminations related to the Air Liquide Welding acquisition. In the six months ended June 30, 2019, special items reflect Rationalization and asset impairment charges of $1,716 and $3,126 in Americas Welding and International Welding, respectively, amortization of step up in value of acquired inventories of $1,399 in Americas Welding, gains on disposals of assets of $3,554 in International Welding and acquisition transaction and integration costs of $1,804 in Corporate / Eliminations related to the Air Liquide Welding acquisition.