MARGIN LENDING, BROKERAGE AND OTHER RECEIVABLES, NET - Narrative (Details) $ in Thousands  | 
 Mar. 31, 2025  
USD ($)  
customer 
 | 
 Mar. 31, 2024  
USD ($)  
customer 
 | 
|---|---|---|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Collateral received, fair value | $ 7,312,950 | $ 2,824,498 | 
| Total margin lending, brokerage and other receivables, net | 3,319,145 | 1,660,275 | 
| Allowance for receivables | 19,256 | 11,990 | 
| Margin lending receivables | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Total margin lending, brokerage and other receivables, net | $ 3,294,569 | $ 1,635,377 | 
| Nonrelated Party | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Number of customers with a margin lending balance exceeding ten percent | customer | 3 | 1 | 
| Collateralized financings | $ 3,218,277 | $ 460,771 | 
| Nonrelated Party | Margin lending receivables | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Total margin lending, brokerage and other receivables, net | $ 2,323,461 | $ 399,196 | 
| X | ||||||||||
- Definition Collateral Received, Fair Value No definition available. 
  | 
| X | ||||||||||
- Definition Number Of Customers With A Margin Lending Balance Exceeding Ten Percent No definition available. 
  | 
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
  | 
| X | ||||||||||
- Definition Amount of allowance for credit loss on accounts receivable. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
  | 
| X | ||||||||||
- Definition The value of the collateral (typically cash) that the entity receives in a financing transaction in exchange for securities lent. This item represents a liability in the financial statements of the lender of the securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  | 
| X | ||||||||||
- Definition Amount due from parties in nontrade transactions, classified as other. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  |