RETIREMENT ANNUITY AND GUARANTEED CONTINUOUS EMPLOYMENT PLANS (Obligations and Funded Status) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in plan assets
Balance at the beginning of year		$ 681,732
Balance at the end of year		612,265	$ 681,732
United States
Change in benefit obligations
Benefit obligations at beginning of year		507,075	484,758
Service cost		139	608	$ 15,474
Interest cost		18,084	19,497	20,676
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		0	0
Acquisitions	[1]	0	0
Actuarial (gain) loss		(46,924)	46,144
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(7,973)	(6,409)
Settlement/curtailment	[2]	(31,456)	(37,523)
Currency translation		0	0
Benefit obligations at end of year		438,945	507,075	484,758
Change in plan assets
Balance at the beginning of year		568,388	528,744
Actual return on plan assets		(23,012)	82,732
Employer contributions		690	55
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant		0	0
Acquisitions	[1]	0	0
Benefits paid		(7,047)	(5,620)
Settlement	[2]	(26,941)	(37,523)
Currency translation		0	0
Balance at the end of year		512,078	568,388	528,744
Net amount recognized
Funded status at end of year		73,133	61,313
Unrecognized actuarial net loss		85,624	90,679
Unrecognized prior service cost		0	0
Unrecognized transition assets, net		0	0
Net amount recognized in the balance sheets		158,757	151,992
Foreign Plan [Member]
Change in benefit obligations
Benefit obligations at beginning of year		193,523	79,972
Service cost		3,252	2,678	2,215
Interest cost		3,703	3,253	2,902
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		196	176
Acquisitions	[1]	(5,322)	100,551
Actuarial (gain) loss		(5,674)	4,926
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(9,723)	(4,909)
Settlement/curtailment	[2]	(1,886)	(700)
Currency translation		(9,258)	7,576
Benefit obligations at end of year		168,811	193,523	79,972
Change in plan assets
Balance at the beginning of year		113,344	70,341
Actual return on plan assets		(2,855)	5,770
Employer contributions		2,087	1,684
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant		196	176
Acquisitions	[1]	586	32,599
Benefits paid		(5,904)	(3,196)
Settlement	[2]	(1,455)	(22)
Currency translation		(5,812)	5,992
Balance at the end of year		100,187	113,344	$ 70,341
Net amount recognized
Funded status at end of year		(68,624)	(80,179)
Unrecognized actuarial net loss		25,581	25,987
Unrecognized prior service cost		534	(11)
Unrecognized transition assets, net		32	35
Net amount recognized in the balance sheets		$ (42,477)	$ (54,168)

[1] Acquisitions in 2017 relate to acquisition of Air Liquide Welding as discussed in Note 4 to the consolidated financial statements.

[2] Settlements in 2018 and 2017 resulting from lump sum pension payments.