Quarterly report [Sections 13 or 15(d)]

INVESTMENT SECURITIES - Schedule of present securities assets at fair value (Details)

v3.25.3
INVESTMENT SECURITIES - Schedule of present securities assets at fair value (Details) - USD ($)
$ in Thousands
Sep. 30, 2025
Mar. 31, 2025
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 1,740,526 $ 2,275,286
Total available-for-sale securities, at fair value 439,801 473,587
Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,740,526 2,275,286
Total available-for-sale securities, at fair value 439,801 473,587
Quoted Prices in Active Markets for Identical Assets | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 956,082 1,444,746
Total available-for-sale securities, at fair value 195,678 241,935
Significant Other Observable Inputs | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 761,990 812,220
Total available-for-sale securities, at fair value 244,123 231,652
Significant Unobservable Units | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 22,454 18,320
Total available-for-sale securities, at fair value 0 0
Non-U.S. sovereign debt    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 977,357 1,282,450
Total available-for-sale securities, at fair value $ 220,214 $ 208,231
Non-U.S. sovereign debt | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Trading securities, weighted average interest rate 11.59% 11.24%
Total trading securities $ 977,357 $ 1,282,450
Total available-for-sale securities, weighted average interest rate 11.47% 9.96%
Total available-for-sale securities, at fair value $ 220,214 $ 208,231
Non-U.S. sovereign debt | Quoted Prices in Active Markets for Identical Assets | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 492,282 987,657
Total available-for-sale securities, at fair value 78,235 128,772
Non-U.S. sovereign debt | Significant Other Observable Inputs | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 485,075 294,793
Total available-for-sale securities, at fair value 141,979 79,459
Non-U.S. sovereign debt | Significant Unobservable Units | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 0 0
Total available-for-sale securities, at fair value 0 0
Corporate debt    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 532,203 807,985
Total available-for-sale securities, at fair value $ 197,676 $ 243,730
Corporate debt | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Trading securities, weighted average interest rate 12.90% 13.93%
Total trading securities $ 532,203 $ 807,985
Total available-for-sale securities, weighted average interest rate 16.11% 14.81%
Total available-for-sale securities, at fair value $ 197,676 $ 243,730
Corporate debt | Quoted Prices in Active Markets for Identical Assets | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 257,185 299,123
Total available-for-sale securities, at fair value 95,532 91,537
Corporate debt | Significant Other Observable Inputs | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 273,945 508,862
Total available-for-sale securities, at fair value 102,144 152,193
Corporate debt | Significant Unobservable Units | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,073 0
Total available-for-sale securities, at fair value 0 0
Corporate equity    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 148,271 $ 106,227
Corporate equity | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Trading securities, weighted average interest rate 0.00% 0.00%
Total trading securities $ 148,271 $ 106,227
Corporate equity | Quoted Prices in Active Markets for Identical Assets | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 125,700 81,810
Corporate equity | Significant Other Observable Inputs | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,190 6,097
Corporate equity | Significant Unobservable Units | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 21,381 18,320
U.S. sovereign debt    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 76,343 73,787
Total available-for-sale securities, at fair value $ 21,911 $ 21,626
U.S. sovereign debt | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Trading securities, weighted average interest rate 3.72% 3.99%
Total trading securities $ 76,343 $ 73,787
Total available-for-sale securities, weighted average interest rate 2.40% 2.73%
Total available-for-sale securities, at fair value $ 21,911 $ 21,626
U.S. sovereign debt | Quoted Prices in Active Markets for Identical Assets | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 76,343 73,787
Total available-for-sale securities, at fair value 21,911 21,626
U.S. sovereign debt | Significant Other Observable Inputs | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 0 0
Total available-for-sale securities, at fair value 0 0
U.S. sovereign debt | Significant Unobservable Units | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 0 0
Total available-for-sale securities, at fair value 0 0
Exchange traded notes and funds    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 6,352 $ 4,837
Exchange traded notes and funds | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Trading securities, weighted average interest rate 0.00% 0.00%
Total trading securities $ 6,352 $ 4,837
Exchange traded notes and funds | Quoted Prices in Active Markets for Identical Assets | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 4,572 2,369
Exchange traded notes and funds | Significant Other Observable Inputs | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,780 2,468
Exchange traded notes and funds | Significant Unobservable Units | Fair value, recurring    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 0 $ 0