RETIREMENT AND DEFERRED COMPENSATION PLANS - Defined Benefit Plans Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
United States
Changes in the benefit obligations and plan assets
Employer contribution	$ 448,000	$ 436,000
Defined Benefit Plan Minimum Funding Requirement By Employer	0
Expected contribution in next fiscal year	500,000
United States | Supplemental Employee Retirement Plan
Changes in the benefit obligations and plan assets
Liability, defined benefit plan	16,800,000	12,600,000
Foreign Plans
Changes in the benefit obligations and plan assets
Employer contribution	7,527,000	$ 6,542,000
Expected contribution in next fiscal year	$ 500,000