COLLATERALIZED ARRANGEMENTS AND FINANCING - Crypto Assets Held as Collateral and Obligation to Return (Details) $ in Thousands	Jun. 30, 2026 USD ($) unit	Dec. 31, 2025 USD ($) unit
Crypto Asset, Holding [Line Items]
Crypto assets held as collateral	$ 1,645,051	$ 822,827
Total recognized lending collateral	1,374,093	799,484
Asset Pledged as Collateral without Right
Crypto Asset, Holding [Line Items]
Total customer collateral not recognized as collateral	1,510,562	1,863,441
Fiat and Payment Stablecoins
Crypto Asset, Holding [Line Items]
Crypto assets held as collateral	11,770	4,056
Fiat and Payment Stablecoins \| Asset Pledged as Collateral without Right
Crypto Asset, Holding [Line Items]
Total customer collateral not recognized as collateral	248,906	303,983
Crypto Assets
Crypto Asset, Holding [Line Items]
Cost Basis	1,714,856	861,078
Crypto assets held as collateral	$ 1,362,323	$ 795,428
Crypto Assets \| Bitcoin
Crypto Asset, Holding [Line Items]
Units \| unit	22,609	8,479
Cost Basis	$ 1,656,622	$ 810,055
Crypto assets held as collateral	$ 1,323,142	$ 747,697
Crypto Assets \| Ethereum
Crypto Asset, Holding [Line Items]
Units \| unit	24,965	16,041
Cost Basis	$ 58,234	$ 51,023
Crypto assets held as collateral	39,181	47,731
Crypto Assets \| Asset Pledged as Collateral without Right
Crypto Asset, Holding [Line Items]
Total customer collateral not recognized as collateral	$ 1,261,656	$ 1,559,458