INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Enacted Corporate Tax									35.00%
New Enacted Corporate Tax Rate									21.00%
Deferred Tax Assets, Operating Loss Carryforwards, Components [Abstract]
Unrecognized tax benefits including the impact of penalties and interest	$ 1,800				$ 1,000				$ 1,800	$ 1,000	$ 26,000
Unrecognized tax benefits that would impact effective tax rate	1,800				1,000				1,800	1,000	3,200
Reconciliation of Income Tax Provision to Statutory Tax Rate [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount									(4,698)	15,870	198
Effective Income Tax Rate Reconciliation, Tax Credit, Amount									(1,646)	(2,468)	(2,972)
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount									3,113	(12,662)	(4,055)
Effective Income Tax Rate Reconciliation, Tax Contingency, Uncertain Tax Positions									800	(6,710)	0
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount									1,109	670	2,303
Effective Income Tax Rate Reconciliation, Deduction, Note Issuance									0	0	(6,493)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount									0	2,509	0
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount									1,455	(84)	9,104
Total (benefit from) provision for income taxes	459	$ (1,065)	$ 587	$ 152	1,108	$ (5,321)	$ 703	$ 635	133	(2,875)	(1,915)
Income (loss) from operations before income taxes:
United States									(4,811)	12,402	(23,977)
Foreign									(8,611)	32,942	24,542
Total income from operations before income taxes	(422)	(993)	(10,244)	(1,763)	6,329	3,797	13,643	21,575	(13,422)	45,344	565
Current tax expense (benefit):
Net cash payments for income taxes									(100)	1,587	2,251
Federal									(4)	102	115
State									59	32	3
Foreign benefit of net operating losses									(66)	(1,247)	(180)
Other foreign									1,774	(48)	3,734
Total current tax expense (benefit)									1,763	(1,161)	3,672
Deferred tax (benefit) expense:
Federal benefit related a Note issuance									0	0	(6,493)
Federal									(821)	96	0
Other foreign									(809)	(1,810)	906
Total deferred tax (benefit) expense									(1,630)	(1,714)	(5,587)
Total (benefit from) provision for income taxes	459	$ (1,065)	$ 587	152	1,108	$ (5,321)	$ 703	635	133	(2,875)	(1,915)
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Unrecognized tax benefits at beginning of period				$ 1,041				$ 25,995	1,041	25,995	25,847
Increases for tax positions taken during a prior period									800	1,041	148
Decreases for tax positions taken during a prior period										(25,995)
Unrecognized tax benefits at end of period	1,841				$ 1,041				1,841	$ 1,041	$ 25,995
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations									129,400
Deferred Tax Assets, Tax Credit Carryforwards	$ 800								$ 800