INCOME TAXES (U.S. Tax Act Effect) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Liability [Abstract]
Income tax payable related to one-time transition tax			$ 64,321
Income tax payable related to transition tax payment period			8 years
Provisional charge adjustment		$ (4,935)	$ (64,321)
Transition tax provisional charge	$ 59,386
Tax Cuts and Jobs Act, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit) [Abstract]
Provisional deferred income tax expense recorded	926	10,311
Total adjustment to deferred tax asset recorded	11,237
Income tax expense (benefit) related to withholding tax payable			$ 4,850
Net income tax benefit resulting from U.S. foreign tax credit for withholding tax	0	$ 4,850
Accumulated undistributed foreign earnings indefinitely reinvested	$ 861,893
United States
Effect of Tax Cuts and Jobs Act, Incomplete Accounting, Provisional [Abstract]
Statutory income tax rate			35.00%
U.S. Tax Cuts and Jobs Act
Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Liability [Abstract]
Income tax rate on foreign cash and certain other net current assets			15.50%
Income tax rate on remaining earnings			8.00%
U.S. Tax Cuts and Jobs Act | United States
Effect of Tax Cuts and Jobs Act, Incomplete Accounting, Provisional [Abstract]
Statutory income tax rate		21.00%
U.S. Tax Cuts and Jobs Act | Belarus
Tax Cuts and Jobs Act, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit) [Abstract]
Accumulated earnings that are no longer indefinitely reinvested			$ 97,000
Income tax expense (benefit) related to withholding tax payable			$ 4,850
Net income tax benefit resulting from U.S. foreign tax credit for withholding tax		$ 4,850