TRADING AND AVAILABLE FOR SALE SECURITIES AT FAIR VALUE (Details) - USD ($)  | 
Jun. 30, 2021  | 
Mar. 31, 2021  | 
|---|---|---|
| Trading securities | $ 825,364,000 | $ 736,188,000 | 
| Total Available-for-sale securities, at fair value | 1,000 | 1,000 | 
| Corporate debt [Member] | ||
| Trading securities | 447,283,000 | 334,763,000 | 
| Preferred Shares | ||
| Total Available-for-sale securities, at fair value | 0 | 1,000 | 
| Equity securities | ||
| Total Available-for-sale securities, at fair value | 1,000 | 1,000 | 
| Total Available-for-sale securities, at fair values | 1 | 0 | 
| Non-U.S. sovereign debt | ||
| Trading securities | 302,086,000 | 333,619,000 | 
| U.S. sovereign debt | ||
| Trading securities | 13,041,000 | 10,828,000 | 
| Corporate equity | ||
| Trading securities | 49,920,000 | 47,340,000 | 
| Exchange traded notes | ||
| Trading securities | $ 13,034,000 | $ 9,638,000 | 
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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. No definition available. 
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- Definition Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer. No definition available. 
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- Definition Amount of investment in marketable security. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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