SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2019 USD ($)		Sep. 30, 2018 USD ($)		Sep. 30, 2019 USD ($) segment		Sep. 30, 2018 USD ($)
Financial information for the reportable segments
Restructuring, Settlement and Impairment Provisions	$ 1,495		$ 2,636		$ 6,337		$ 24,353
Number of operating segments | segment					3
Net sales	730,783		737,099		$ 2,266,965		2,284,847
Inter-segment sales	0		0		0		0
Total	730,783		737,099		2,266,965		2,284,847
EBIT, as adjusted	93,700		107,551		305,814		320,435
Special items charge (gain)	(4,497)	[1]	7,838	[2]	(6)	[1]	33,008	[2]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Gain (Loss) Due to Settlement and Curtailment			(4,232)				(4,990)
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net	7,601				7,601		0
EBIT	98,197		99,713		305,820		287,427
Interest income	491		1,993		2,047		5,273
Interest expense	(6,891)		(5,962)		(19,668)		(18,495)
Income before income taxes	91,797		95,744		288,199		274,205
The Harris Products Group
Financial information for the reportable segments
Net sales	81,884		73,467		253,348		233,235
Inter-segment sales	1,857		1,537		5,837		5,447
Total	83,741		75,004		259,185		238,682
EBIT, as adjusted	11,038		8,676		35,045		28,058
Special items charge (gain)	0	[1]	0	[2]	0	[1]	0	[2]
EBIT	11,038		8,676		35,045		28,058
Corporate / Eliminations
Financial information for the reportable segments
Acquisition Transaction and Integration Costs			970		1,804		3,665
Net sales	0		0		0		0
Inter-segment sales	(37,399)		(37,045)		(113,975)		(108,787)
Total	(37,399)		(37,045)		(113,975)		(108,787)
EBIT, as adjusted	(1,632)		(1,099)		(8,643)		(4,443)
Special items charge (gain)	0	[1]	970	[2]	1,804	[1]	3,665	[2]
EBIT	(1,632)		(2,069)		(10,447)		(8,108)
Americas Welding
Financial information for the reportable segments
Restructuring, Settlement and Impairment Provisions					1,716
Net sales	443,521		454,010		1,377,847		1,351,297
Inter-segment sales	31,101		31,845		95,300		89,671
Total	474,622		485,855		1,473,147		1,440,968
EBIT, as adjusted	74,110		89,253		240,713		254,850
Special items charge (gain)	0	[1]	4,232	[2]	3,115	[1]	4,990	[2]
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Gain (Loss) Due to Settlement and Curtailment			(4,232)				(4,990)
Business Combination, Inventory Step Up					1,399
EBIT	74,110		85,021		237,598		249,860
International Welding
Financial information for the reportable segments
Restructuring, Settlement and Impairment Provisions	1,495		2,636		4,621		24,353
Net sales	205,378		209,622		635,770		700,315
Inter-segment sales	4,441		3,663		12,838		13,669
Total	209,819		213,285		648,608		713,984
EBIT, as adjusted	10,184		10,721		38,699		41,970
Special items charge (gain)	(4,497)	[1]	2,636	[2]	(4,925)	[1]	24,353	[2]
Business Combination, Inventory Step Up	1,609				1,609
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net	7,601				7,601
Gain (Loss) on Disposition of Assets					3,554
EBIT	$ 14,681		$ 8,085		$ 43,624		$ 17,617

[1] In the three months ended September 30, 2019, special items reflect Rationalization and asset impairment charges of $1,495, amortization of step up in value of acquired inventories of $1,609 related to the acquisition of Askaynak and gain on change in control of $7,601 related to the acquisition of Askaynak in International Welding. In the nine months ended September 30, 2019, special items reflect Rationalization and asset impairment charges of $1,716 in Americas Welding and $4,621 in International Welding, amortization of step up in value of acquired inventories of $1,399 related to the acquisition of Baker Industries in Americas Welding and $1,609 related to the acquisition of Askaynak in International 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 and a gain on change in control of $7,601 related to the acquisition of Askaynak.

[2] In the three months ended September 30, 2018, special items reflect pension settlement charges of $4,232 in Americas Welding, rationalization and asset impairment charges of $2,636 in International Welding and transaction and integration costs of $970 in Corporate / Eliminations related to the Air Liquide Welding acquisition. In the nine months ended September 30, 2018, special items reflect pension settlement charges of $4,990 in Americas Welding, Rationalization and asset impairment charges of $24,353 in International Welding and acquisition transaction and integration costs of $3,665 in Corporate / Eliminations related to the Air Liquide Welding acquisition.