GOODWILL AND INTANGIBLES (Changes in Carrying Amount of Goodwill by Reportable Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Changes in the carrying amount of goodwill by reportable segment
Balance at the beginning of the period	$ 281,294		$ 234,582
Additions and adjustments	53,987	[1]	52,157	[2]
Foreign currency translation	1,826		(5,445)
Balance at the end of the period	337,107		281,294		$ 234,582
Americas Welding [Member]
Changes in the carrying amount of goodwill by reportable segment
Balance at the beginning of the period	239,215		197,259
Additions and adjustments	37,346	[1]	44,408	[2]
Impairment charge					(1,091)
Foreign currency translation	1,935		(2,452)
Balance at the end of the period	278,496		239,215		197,259
International Welding [Member]
Changes in the carrying amount of goodwill by reportable segment
Balance at the beginning of the period	24,248		25,667
Additions and adjustments	17,254	[1]	1,224	[2]
Foreign currency translation	(28)		(2,643)
Balance at the end of the period	41,474		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	17,831		11,656
Additions and adjustments	(613)	[1]	6,525	[2]
Foreign currency translation	(81)		(350)
Balance at the end of the period	$ 17,137		$ 17,831		$ 11,656

[1] Additions to Americas Welding reflect goodwill recognized in the acquisition of Baker in 2019. Additions to International Welding reflect goodwill recognized in the acquisition of Askaynak in 2019.

[2] 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.