EMPLOYEE BENEFIT PLANS (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Pension_Plan	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Amounts recognized in balance sheet:
Noncurrent liabilities	$ (38,288)	$ (38,020)
United States
Defined Benefit Plan, Change in Benefit Obligation
Number of pension plans | Pension_Plan	2
GERMANY
Defined Benefit Plan, Change in Benefit Obligation
Number of pension plans | Pension_Plan	3
Other Benefits
Net Periodic Benefit Cost and Other Benefit Cost
Accumulated benefit obligation, end of year	$ 8,300	9,100
Defined Benefit Plan, Change in Benefit Obligation
Benefit obligation, beginning of year	9,100	10,300
Service cost	0	0	$ 0
Interest cost	300	300	300
Actuarial (gain)/loss	(200)	(500)
Settlements paid	0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid	900	1,000
Foreign currency exchange	0	0
Benefit obligation, end of year	$ 8,300	9,100	10,300
Actuarially reduced benefits for employees who retire before defined age	65 years
Defined Benefit Plan, Change in Fair Value of Plan Assets
Fair value of assets, beginning of year	$ 0	0
Actual return on plan assets	0	0
Company contributions	900	1,000
Settlements paid	0	0
Defined Benefit Plan, Plan Assets, Benefits Paid	900	1,000
Foreign currency exchange	0	0
Plan assets, end of year	0	0	0
Funded status	(8,300)	(9,100)
Amounts recognized in balance sheet:
Current liabilities	(800)	(1,000)
Noncurrent liabilities	(7,500)	(8,100)
Net liability, end of year	(8,300)	(9,100)
Amount recognized in accumulated other comprehensive income/(loss):
Prior service cost	0	0
Net actuarial loss	400	600
Settlement	0	0
Total recognized in accumulated other comprehensive income/(loss)	400	600
Pension Benefits
Net Periodic Benefit Cost and Other Benefit Cost
Accumulated benefit obligation, end of year	176,500	164,900
Defined Benefit Plan, Change in Benefit Obligation
Benefit obligation, beginning of year	168,900	185,100
Service cost	700	600	700
Interest cost	5,800	5,400	5,600
Actuarial (gain)/loss	17,000	(9,500)
Settlements paid	(700)	(300)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	10,300	11,400
Foreign currency exchange	(500)	(1,000)
Benefit obligation, end of year	180,900	168,900	185,100
Defined Benefit Plan, Change in Fair Value of Plan Assets
Fair value of assets, beginning of year	140,100	153,300
Actual return on plan assets	20,000	(3,800)
Company contributions	2,000	2,500
Settlements paid	(500)	(300)
Defined Benefit Plan, Plan Assets, Benefits Paid	10,300	11,400
Foreign currency exchange	(100)	(200)
Plan assets, end of year	151,200	140,100	$ 153,300
Funded status	(29,700)	(28,800)
Amounts recognized in balance sheet:
Current liabilities	(500)	(400)
Noncurrent liabilities	(29,200)	(28,400)
Net liability, end of year	(29,700)	(28,800)
Amount recognized in accumulated other comprehensive income/(loss):
Prior service cost	0	0
Net actuarial loss	49,000	47,500
Settlement	600	400
Total recognized in accumulated other comprehensive income/(loss)	$ 49,600	$ 47,900