v3.26.1
INVESTMENT SECURITIES - Schedule of present securities assets at fair value (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Mar. 31, 2026
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 2,974,677 $ 2,339,100
Total available-for-sale securities, at fair value 686,784 574,038
Quoted Prices in Active Markets for Identical Assets    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,450,228 1,416,580
Total available-for-sale securities, at fair value 302,929 227,144
Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,501,034 900,245
Total available-for-sale securities, at fair value 383,855 346,894
Significant Unobservable Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 23,415 22,275
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 11.20% 10.06%
Total trading securities $ 2,073,085 $ 1,337,577
Total available-for-sale securities, weighted average interest rate 8.71% 8.85%
Total available-for-sale securities, at fair value $ 242,009 $ 240,453
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 816,276 693,830
Total available-for-sale securities, at fair value 41,140 74,055
Non-U.S. sovereign debt | Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,256,809 643,747
Total available-for-sale securities, at fair value 200,869 166,398
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 15.43% 16.80%
Total trading securities $ 682,474 $ 793,850
Total available-for-sale securities, weighted average interest rate 16.84% 16.41%
Total available-for-sale securities, at fair value $ 422,690 $ 311,604
Corporate debt | Quoted Prices in Active Markets for Identical Assets    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 444,449 542,401
Total available-for-sale securities, at fair value 239,704 131,108
Corporate debt | Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 236,948 250,371
Total available-for-sale securities, at fair value 182,986 180,496
Corporate debt | Significant Unobservable Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,077 1,078
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 $ 148,815 $ 166,394
Corporate equity | Quoted Prices in Active Markets for Identical Assets    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 124,554 141,270
Corporate equity | Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 1,923 3,927
Corporate equity | Significant Unobservable Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 22,338 $ 21,197
U.S. sovereign debt    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Trading securities, weighted average interest rate 4.14% 3.89%
Total trading securities $ 32,778 $ 33,060
Total available-for-sale securities, weighted average interest rate 1.88% 2.03%
Total available-for-sale securities, at fair value $ 22,085 $ 21,981
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 32,778 33,060
Total available-for-sale securities, at fair value 22,085 21,981
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 $ 37,525 $ 8,219
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 32,171 6,019
Exchange traded notes and funds | Significant Other Observable Inputs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities 5,354 2,200
Exchange traded notes and funds | Significant Unobservable Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total trading securities $ 0 $ 0