FAIR VALUE DISCLOSURES - Financial instruments measured at fair value on recurring basis (Details) - Fair value on a recurring basis - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets:
Equity securities	$ 228	$ 197
Debt Securities, Trading, and Equity Securities, FV-NI	30,194	31,738
Level 1
Assets:
Equity securities	$ 228	$ 197

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Name:	us-gaap_TradingSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant