SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of financial assets measured on nonrecurring basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in nonpublic entities that do not report NAV	$ 16,011	$ 0
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in nonpublic entities that do not report NAV	0	0
Other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in nonpublic entities that do not report NAV	15,511	0
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in nonpublic entities that do not report NAV	$ 500	$ 0