Annual report pursuant to Section 13 and 15(d)

TRADING AND AVAILABLE-FOR-SALE SECURITIES AT FAIR VALUE - Schedule of valuation techniques and significant level 3 inputs used in the valuation (Details)

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TRADING AND AVAILABLE-FOR-SALE SECURITIES AT FAIR VALUE - Schedule of valuation techniques and significant level 3 inputs used in the valuation (Details)
$ in Thousands
 12 Months Ended
Mar. 31, 2024
USD ($)
times
Mar. 31, 2023
USD ($)
Mar. 31, 2022
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Trading securities $ 3,688,620 $ 2,412,556 $ 1,158,377
Corporate debt | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Estimated number of years 3 months    
Corporate debt | Valuation technique, discounted cash flow | Discount rate      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Measurement input 0.740    
Corporate equity | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Estimated number of years 4 years 6 months    
Corporate equity | Valuation technique, discounted cash flow | Discount rate      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Measurement input 0.130    
Corporate equity | Valuation technique, discounted cash flow | Termination multiplier      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Measurement input | times 27    
Corporate equity | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Estimated number of years 9 years 9 years  
Corporate equity | Valuation technique, discounted cash flow | Discount rate      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Measurement input 0.588 0.588  
Non-U.S. sovereign debt | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Estimated number of years   11 years  
Non-U.S. sovereign debt | Valuation technique, discounted cash flow | Discount rate      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Measurement input   0.488  
Corporate debt | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Estimated number of years   3 months  
Corporate debt | Valuation technique, discounted cash flow | Discount rate      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Measurement input   0.740  
Fair Value, Inputs, Level 3 [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Trading securities $ 20,442 $ 5,138  
Fair Value, Inputs, Level 3 [Member] | Corporate debt | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Trading securities 292    
Fair Value, Inputs, Level 3 [Member] | Corporate equity | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Trading securities 20,007    
Fair Value, Inputs, Level 3 [Member] | Corporate equity | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Trading securities $ 143 962  
Fair Value, Inputs, Level 3 [Member] | Non-U.S. sovereign debt | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Trading securities   3,776  
Fair Value, Inputs, Level 3 [Member] | Corporate debt | Valuation technique, discounted cash flow      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Trading securities   $ 400