GOODWILL AND INTANGIBLES (Changes in Carrying Amount of Goodwill by Reportable Segment) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017
Changes in the carrying amount of goodwill by reportable segment
Balance at the beginning of the period		$ 234,582		$ 231,919
Additions and adjustments		52,157	[1]	(377)	[2]
Impairment charge	[3]			(1,091)
Foreign currency translation		(5,445)		4,131
Balance at the end of the period		281,294		234,582
Americas Welding [Member]
Changes in the carrying amount of goodwill by reportable segment
Balance at the beginning of the period		197,259		196,378
Additions and adjustments		44,408	[1]	(76)	[2]
Impairment charge	[3]			(1,091)
Foreign currency translation		(2,452)		2,048
Balance at the end of the period		239,215		197,259
International Welding [Member]
Changes in the carrying amount of goodwill by reportable segment
Balance at the beginning of the period		25,667		23,664
Additions and adjustments		1,224	[1]	0	[2]
Impairment charge	[3]			0
Foreign currency translation		(2,643)		2,003
Balance at the end of the period		24,248		25,667
The Harris Products Group
Changes in the carrying amount of goodwill by reportable segment
Balance at the beginning of the period		11,656		11,877
Additions and adjustments		6,525	[1]	(301)	[2]
Impairment charge	[3]			0
Foreign currency translation		(350)		80
Balance at the end of the period		$ 17,831		$ 11,656

[1] Additions to Americas Welding reflect goodwill recognized in the acquisitions of Coldwater, Pro Systems and Inovatech in 2018. Additions to The Harris Products Group reflect goodwill recognized in the acquisition of Worthington in 2018.

[2] Adjustments to Harris Products Group include the tax benefit attributable to the amortization of tax deductible goodwill in excess of goodwill recorded for financial reporting purposes.

[3] The Company performed an interim goodwill impairment test, using a combination of income and market valuation approaches, resulting in a non-cash impairment charge to the carrying value of goodwill. The impairment charge is recorded within Rationalization and asset impairment charges in the accompanying Consolidated Statements of Income.