ACCRUED LIABILITIES - Summary of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Compensation and benefits payable	$ 3,601	$ 7,190
Property, sales, and other taxes	1,350	785
Customer credit balances	1,730	2,204
Accrued interest	953	1,762
Other	3,087	3,266
Accrued liabilities, current, total	$ 10,721	$ 15,207	$ 17,617	$ 14,196	$ 16,226

Amount payable to customer by broker-dealer.

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Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying value as of the balance sheet date of liabilities incurred through that date and payable for statutory sales and use taxes, including value added tax. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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