RETIREMENT AND DEFERRED COMPENSATION PLANS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
United States
Change in benefit obligation:
Benefit obligation at beginning of year	$ 180,803	$ 198,450
Service cost	11,093	11,396	$ 9,706
Interest cost	7,381	6,878	7,010
Actuarial (gain) loss	39,209	(23,510)
Benefits paid	(11,211)	(12,411)
Benefit obligation at end of year	227,275	180,803	198,450
Change in plan assets:
Fair value of plan assets at beginning of year	169,958	169,600
Actual return on plan assets	29,618	(7,642)
Employer contribution	436	20,411
Benefits paid	(11,211)	(12,411)
Fair value of plan assets at end of year	188,801	169,958	169,600
Funded status at end of year				$ (38,474)	$ (10,845)
Funded status amounts recognized in Consolidated Balance Sheet
Non-current assets					207
Current liabilities				(449)	(430)
Non-current liabilities				(38,025)	(10,622)
Funded status amount				(38,474)	(10,845)
Amounts recognized in accumulated other comprehensive loss
Net actuarial loss				68,789	48,776
Tax effects				(15,821)	(17,876)
Net amount recognized				52,968	30,900
Changes in benefit obligations and plan assets recognized in other comprehensive income
Current year actuarial gain (loss)	(21,970)	4,611	(12,593)
Amortization of net loss	1,957	4,873	3,205
Net amount recognized	(20,013)	9,484	(9,388)
Amounts in accumulated other comprehensive loss expected to be recognized as components of periodic benefit cost in next fiscal year
Amortization of net loss				5,719
Amount expected to be recognized in next fiscal year				5,719
Components of net periodic benefit cost:
Service cost	11,093	11,396	9,706
Interest cost	7,381	6,878	7,010
Expected return on plan assets	(12,379)	(11,257)	(9,880)
Amortization of net loss	1,957	4,873	3,205
Net periodic benefit cost	$ 8,052	$ 11,890	$ 10,041
Accumulated benefit obligation				205,300	163,000
Projected benefit obligation ("PBO"), ABO, and fair value of plan assets for all pension plans with an ABO in excess of plan assets
Projected benefit obligation				227,275	11,052
Accumulated benefit obligation				205,326	9,216
Fair value of plan assets				188,801
PBO, ABO, and fair value of plan assets for all pension plans with a PBO in excess of plan assets
Projected benefit obligation				227,275	11,052
Accumulated benefit obligation				205,326	$ 9,216
Fair value of plan assets				$ 188,801
Weighted-average assumptions used to determine benefit obligations
Discount rate (as a percent)				3.20%	4.20%	3.55%
Rate of compensation increase (as a percent)				4.00%	4.00%	4.00%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)	4.20%	3.55%	4.05%
Expected long-term return on plan assets (as a percent)	7.00%	7.00%	7.00%
Rate of compensation increase (as a percent)	4.00%	4.00%	4.00%
Plan Assets:
Weighted-average asset allocations (as a percent)				100.00%	100.00%
Total Investments in Fair Value Hierarchy				$ 119,883	$ 107,943
Total Investments	$ 188,801	$ 169,600	$ 169,600	188,801	169,958	$ 169,600
Minimum funding requirement	0
Expected contribution in next fiscal year				400
United States | Cash and Short Term Securities
Plan Assets:
Total Investments in Fair Value Hierarchy				$ 1,988	$ 8,964
United States | Equity Securities
Plan Assets:
Weighted-average asset allocations (as a percent)				49.00%	44.00%
Target allocation (as a percent)				60.00%
Total Investments in Fair Value Hierarchy				$ 81,997	$ 66,707
United States | Fixed Income Funds
Plan Assets:
Weighted-average asset allocations (as a percent)				29.00%	29.00%
Total Investments in Fair Value Hierarchy				$ 35,898	$ 32,272
United States | Hedge Fund
Plan Assets:
Weighted-average asset allocations (as a percent)				10.00%	10.00%
United States | Infrastructure
Plan Assets:
Weighted-average asset allocations (as a percent)				6.00%	7.00%
United States | Money market
Plan Assets:
Weighted-average asset allocations (as a percent)				1.00%	5.00%
United States | Fixed income securities and infrastructure
Plan Assets:
Target allocation (as a percent)				40.00%
United States | Real Estate Funds
Plan Assets:
Weighted-average asset allocations (as a percent)				5.00%	5.00%
United States | Level 1
Change in plan assets:
Fair value of plan assets at beginning of year	107,943
Fair value of plan assets at end of year	119,883	107,943
Plan Assets:
Total Investments in Fair Value Hierarchy				$ 119,883	$ 107,943
Total Investments	107,943	107,943		119,883	107,943
United States | Level 1 | Cash and Short Term Securities
Plan Assets:
Total Investments in Fair Value Hierarchy				1,988	8,964
United States | Level 1 | Cash and Short Term Securities | USD
Plan Assets:
Total Investments in Fair Value Hierarchy				1,988	8,964
United States | Level 1 | Equity Securities
Plan Assets:
Total Investments in Fair Value Hierarchy				81,997	66,707
United States | Level 1 | US Large Cap Equities
Plan Assets:
Total Investments in Fair Value Hierarchy				48,580	38,804
United States | Level 1 | US Small Cap Equities
Plan Assets:
Total Investments in Fair Value Hierarchy				9,921	7,747
United States | Level 1 | International Equities
Plan Assets:
Total Investments in Fair Value Hierarchy				23,496	20,156
United States | Level 1 | Fixed Income Funds
Plan Assets:
Total Investments in Fair Value Hierarchy				35,898	32,272
United States | Net Asset Value per Share
Plan Assets:
Investments at Net Asset Value per Share				68,918	62,015
Foreign Plans
Change in benefit obligation:
Benefit obligation at beginning of year	104,911	109,030
Service cost	5,921	5,954	5,526
Interest cost	2,023	1,828	1,747
Special termination benefit charge	64	62
Plan amendment	18
Curtailment/Settlement	(271)	(1,751)
Transfer	939
Business acquired		1,937
Prior service cost	(451)	35
Actuarial (gain) loss	13,575	(3,743)
Benefits paid	(4,130)	(3,288)
Foreign currency translation adjustment	(2,109)	(5,153)
Benefit obligation at end of year	120,490	104,911	109,030
Change in plan assets:
Fair value of plan assets at beginning of year	68,992	73,384
Actual return on plan assets	3,851	(487)
Employer contribution	6,542	2,780
Benefits paid	(4,130)	(3,288)
Transfer	359
Foreign currency translation adjustment	(1,425)	(3,397)
Fair value of plan assets at end of year	74,189	68,992	73,384
Funded status at end of year				(46,301)	(35,919)
Funded status amounts recognized in Consolidated Balance Sheet
Non-current assets				938	500
Current liabilities				(44)	(8)
Non-current liabilities				(47,195)	(36,411)
Funded status amount				(46,301)	(35,919)
Amounts recognized in accumulated other comprehensive loss
Net actuarial loss				40,442	29,761
Net prior service cost				3,774	4,656
Tax effects				(14,040)	(4,855)
Net amount recognized				30,176	29,562
Changes in benefit obligations and plan assets recognized in other comprehensive income
Current year actuarial gain (loss)	(11,999)	534	2,952
Current year prior service cost	451	(35)	(1,399)
Transfer Prior service cost	(18)
Transfer Actuarial (loss) gain	(126)
Recognition due to curtailment		1,692
Amortization of net loss	1,444	1,716	1,895
Amortization of prior service cost	449	720	400
Net amount recognized	(9,799)	4,627	3,848
Amounts in accumulated other comprehensive loss expected to be recognized as components of periodic benefit cost in next fiscal year
Amortization of net loss				2,092
Amortization of prior service cost				391
Amount expected to be recognized in next fiscal year				2,483
Components of net periodic benefit cost:
Service cost	5,921	5,954	5,526
Interest cost	2,023	1,828	1,747
Expected return on plan assets	(2,366)	(2,610)	(2,409)
Amortization of net loss	1,444	1,716	1,895
Amortization of prior service cost	449	720	400
Net periodic benefit cost	7,471	7,608	7,159
Curtailment	(246)	(59)
Special termination benefit charge	65	62
Total net periodic benefit cost	$ 7,290	$ 7,611	$ 7,159
Accumulated benefit obligation				91,800	80,900
Projected benefit obligation ("PBO"), ABO, and fair value of plan assets for all pension plans with an ABO in excess of plan assets
Projected benefit obligation				92,561	93,029
Accumulated benefit obligation				65,062	68,981
Fair value of plan assets				46,371	56,611
PBO, ABO, and fair value of plan assets for all pension plans with a PBO in excess of plan assets
Projected benefit obligation				102,310	92,555
Accumulated benefit obligation				73,943	68,506
Fair value of plan assets				$ 55,260	$ 56,136
Weighted-average assumptions used to determine benefit obligations
Discount rate (as a percent)				1.04%	1.82%	1.62%
Rate of compensation increase (as a percent)				3.05%	3.01%	3.02%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)	1.84%	1.62%	1.65%
Expected long-term return on plan assets (as a percent)	3.69%	3.66%	3.66%
Rate of compensation increase (as a percent)	3.05%	3.02%	3.00%
Plan Assets:
Weighted-average asset allocations (as a percent)				100.00%	100.00%
Total Investments in Fair Value Hierarchy				$ 74,189	$ 68,992
Total Investments	$ 68,992	$ 68,992	$ 73,384	74,189	68,992	$ 73,384
Expected contribution in next fiscal year				700
Foreign Plans | Cash and Short Term Securities
Plan Assets:
Total Investments in Fair Value Hierarchy				$ 2,030	$ 718
Foreign Plans | Equity Securities
Plan Assets:
Weighted-average asset allocations (as a percent)				4.00%	4.00%
Total Investments in Fair Value Hierarchy				$ 2,995	$ 2,591
Foreign Plans | Fixed Income Funds
Plan Assets:
Weighted-average asset allocations (as a percent)				1.00%	1.00%
Total Investments in Fair Value Hierarchy				$ 820	$ 717
Foreign Plans | Corporate debts securities
Plan Assets:
Weighted-average asset allocations (as a percent)				3.00%	3.00%
Total Investments in Fair Value Hierarchy				$ 2,115	$ 2,097
Foreign Plans | Investment Funds
Plan Assets:
Weighted-average asset allocations (as a percent)				89.00%	91.00%
Target allocation (as a percent)				100.00%
Total Investments in Fair Value Hierarchy				$ 66,229	$ 62,869
Foreign Plans | Money market
Plan Assets:
Weighted-average asset allocations (as a percent)				3.00%	1.00%
Foreign Plans | Level 1
Change in plan assets:
Fair value of plan assets at beginning of year	28,245
Fair value of plan assets at end of year	31,757	28,245
Plan Assets:
Total Investments in Fair Value Hierarchy				$ 31,757	$ 28,245
Total Investments	28,245	28,245		31,757	28,245
Foreign Plans | Level 1 | Cash and Short Term Securities
Plan Assets:
Total Investments in Fair Value Hierarchy				2,030	718
Foreign Plans | Level 1 | Cash and Short Term Securities | EUR
Plan Assets:
Total Investments in Fair Value Hierarchy				2,012	718
Foreign Plans | Level 1 | Cash and Short Term Securities | Others
Plan Assets:
Total Investments in Fair Value Hierarchy				18
Foreign Plans | Level 1 | Equity Securities
Plan Assets:
Total Investments in Fair Value Hierarchy				2,995	2,591
Foreign Plans | Level 1 | International Equities
Plan Assets:
Total Investments in Fair Value Hierarchy				2,995	2,591
Foreign Plans | Level 1 | Fixed Income Funds
Plan Assets:
Total Investments in Fair Value Hierarchy				820	717
Foreign Plans | Level 1 | Corporate debts securities
Plan Assets:
Total Investments in Fair Value Hierarchy				2,115	2,097
Foreign Plans | Level 1 | Euro Corporate Bonds
Plan Assets:
Total Investments in Fair Value Hierarchy				2,115	2,097
Foreign Plans | Level 1 | Investment Funds
Plan Assets:
Total Investments in Fair Value Hierarchy				23,797	22,122
Foreign Plans | Level 1 | Mutual Funds in Equities
Plan Assets:
Total Investments in Fair Value Hierarchy				4,025	3,339
Foreign Plans | Level 1 | Mutual Funds in Bonds
Plan Assets:
Total Investments in Fair Value Hierarchy				18,881	18,060
Foreign Plans | Level 1 | Mutual Funds Diversified
Plan Assets:
Total Investments in Fair Value Hierarchy				891	723
Foreign Plans | Level 2
Change in plan assets:
Fair value of plan assets at beginning of year	40,747
Fair value of plan assets at end of year	42,432	40,747
Plan Assets:
Total Investments in Fair Value Hierarchy				42,432	40,747
Total Investments	$ 40,747	$ 40,747		42,432	40,747
Foreign Plans | Level 2 | Investment Funds
Plan Assets:
Total Investments in Fair Value Hierarchy				42,432	40,747
Foreign Plans | Level 2 | Mutual Funds Diversified
Plan Assets:
Total Investments in Fair Value Hierarchy				42,432	40,747
Non-qualified supplemental pension plan | United States
Non-qualified supplemental pension plan information
Non funded liability				$ 12,600	$ 11,100