INCOME TAXES - Schedule of net deferred tax liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
INCOME TAXES
Non-current deferred income tax benefits	$ 2,487	$ 1,277
Non-current deferred income tax liabilities	(3,085)	(3,724)
Net deferred income tax liabilities	$ (598)	$ (2,447)

Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=116821951&loc=d3e31931-109318

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

Name:	us-gaap_DeferredTaxLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant