RETIREMENT AND DEFERRED COMPENSATION PLANS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
United States
Change in benefit obligation:
Service cost	$ 2,773	$ 2,849
Interest cost	1,845	1,720
Change in plan assets:
Employer contribution	365
Components of net periodic benefit cost:
Service cost	2,773	2,849
Interest cost	1,845	1,720
Expected return on plan assets	(3,094)	(2,814)
Amortization of net loss	489	1,218
Net periodic benefit cost	2,013	2,973
Minimum funding requirements	0
Foreign Plans
Change in benefit obligation:
Service cost	1,460	1,531
Interest cost	501	472
Change in plan assets:
Employer contribution	700
Components of net periodic benefit cost:
Service cost	1,460	1,531
Interest cost	501	472
Expected return on plan assets	(592)	(679)
Amortization of net loss	363	446
Amortization of prior service cost	113	129
Net periodic benefit cost	1,845	$ 1,899
Expected contribution in current fiscal year	$ 4,300