Quarterly report [Sections 13 or 15(d)]

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

v3.25.4
INVESTMENT SECURITIES - Schedule of present securities assets at fair value (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Mar. 31, 2025
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 2,183,567 $ 2,275,286
Total available-for-sale securities, at fair value 521,543 473,587
Quoted Prices in Active Markets for Identical Assets    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,121,664 1,444,746
Total available-for-sale securities, at fair value 171,559 241,935
Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,040,280 812,220
Total available-for-sale securities, at fair value 349,984 231,652
Significant Unobservable Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 21,623 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]    
Trading securities, weighted average interest rate 9.99% 11.24%
Total trading securities $ 1,258,870 $ 1,282,450
Total available-for-sale securities, weighted average interest rate 9.97% 9.96%
Total available-for-sale securities, at fair value $ 169,088 $ 208,231
Non-U.S. sovereign debt | Quoted Prices in Active Markets for Identical Assets    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 486,623 987,657
Total available-for-sale securities, at fair value 27,824 128,772
Non-U.S. sovereign debt | Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 772,247 294,793
Total available-for-sale securities, at fair value 141,264 79,459
Non-U.S. sovereign debt | Significant Unobservable Units    
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]    
Trading securities, weighted average interest rate 15.40% 13.93%
Total trading securities $ 727,939 $ 807,985
Total available-for-sale securities, weighted average interest rate 16.94% 14.81%
Total available-for-sale securities, at fair value $ 330,400 $ 243,730
Corporate debt | Quoted Prices in Active Markets for Identical Assets    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 463,123 299,123
Total available-for-sale securities, at fair value 121,680 91,537
Corporate debt | Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 263,782 508,862
Total available-for-sale securities, at fair value 208,720 152,193
Corporate debt | Significant Unobservable Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,034 0
Total available-for-sale securities, at fair value $ 0 $ 0
Corporate equity    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Trading securities, weighted average interest rate 0.00% 0.00%
Total trading securities $ 157,481 $ 106,227
Corporate equity | Quoted Prices in Active Markets for Identical Assets    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 134,254 81,810
Corporate equity | Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 2,638 6,097
Corporate equity | Significant Unobservable Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 20,589 $ 18,320
U.S. sovereign debt    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Trading securities, weighted average interest rate 3.66% 3.99%
Total trading securities $ 33,184 $ 73,787
Total available-for-sale securities, weighted average interest rate 2.57% 2.73%
Total available-for-sale securities, at fair value $ 22,055 $ 21,626
U.S. sovereign debt | Quoted Prices in Active Markets for Identical Assets    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 33,184 73,787
Total available-for-sale securities, at fair value 22,055 21,626
U.S. sovereign debt | Significant Other Observable Inputs    
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    
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]    
Trading securities, weighted average interest rate 0.00% 0.00%
Total trading securities $ 6,093 $ 4,837
Exchange traded notes and funds | Quoted Prices in Active Markets for Identical Assets    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 4,480 2,369
Exchange traded notes and funds | Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,613 2,468
Exchange traded notes and funds | Significant Unobservable Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 0 $ 0