INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax Credit Carryforward [Line Items]
Valuation allowance	$ 11,436	$ 8,458
Tax Cuts And Jobs Act Of 2017, incomplete accounting, change in tax rate, provisional income tax expense	800
Tax Cuts And Jobs Act Of 2017, incomplete accounting, transition tax for accumulated foreign earnings, provisional income tax expense	1,700
Foreign earnings intended to be repatriated		25,000
Tax Cuts And Jobs Act Of 2017, incomplete accounting, change in tax rate, deferred tax liability, provisional income tax benefit	1,300
Unrecognized tax benefits	157	733	$ 715
Unrecognized tax benefits, accrued interest and penalties	100	300
Unrecognized tax benefits, income tax penalties and expense	9	$ 42
Current Liabilities
Tax Credit Carryforward [Line Items]
Unrecognized tax benefits	200
Other Long-term Liabilities
Tax Credit Carryforward [Line Items]
Unrecognized tax benefits	200
Foreign Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	5,500
Charitable Contribution Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 200