Annual report [Section 13 and 15(d), not S-K Item 405]

INVESTMENT SECURITIES - Schedule of valuation techniques and significant level 3 inputs used in the valuation (Details)

v3.26.1
INVESTMENT SECURITIES - Schedule of valuation techniques and significant level 3 inputs used in the valuation (Details)
$ in Thousands
 12 Months Ended
Mar. 31, 2026
USD ($)
times
Mar. 31, 2025
USD ($)
times
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Debt securities $ 2,339,100 $ 2,275,286
Fair Value, Inputs, Level 3    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Debt securities 22,275 18,320
Fair Value, Inputs, Level 3 | Corporate Equity, 3 Years | Valuation technique, discounted cash flow    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Debt securities $ 18,840  
Estimated number of years 3 years  
Fair Value, Inputs, Level 3 | Corporate Equity, 3 Years | Valuation technique, discounted cash flow | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 0.090  
Fair Value, Inputs, Level 3 | Corporate Equity, 3 Years | Valuation technique, discounted cash flow | Termination multiplier    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input | times 10.5  
Fair Value, Inputs, Level 3 | Corporate Equity, 6 Years | Valuation technique, discounted cash flow    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Debt securities $ 2,223  
Estimated number of years 6 years  
Fair Value, Inputs, Level 3 | Corporate Equity, 6 Years | Valuation technique, discounted cash flow | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 0.1036  
Fair Value, Inputs, Level 3 | Corporate Equity, 6 Years | Valuation technique, discounted cash flow | Termination multiplier    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input | times 0.935  
Fair Value, Inputs, Level 3 | Corporate Equity, 2 Years | Valuation technique, discounted cash flow    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Debt securities $ 1,078 $ 18,193
Estimated number of years 2 years 2 years
Fair Value, Inputs, Level 3 | Corporate Equity, 2 Years | Valuation technique, discounted cash flow | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 0.132 0.215
Fair Value, Inputs, Level 3 | Corporate Equity, 2 Years | Valuation technique, discounted cash flow | Termination multiplier    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input | times   19.5
Fair Value, Inputs, Level 3 | Corporate Equity, 9 years | Valuation technique, discounted cash flow    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Debt securities $ 134 $ 127
Estimated number of years 9 years 9 years
Fair Value, Inputs, Level 3 | Corporate Equity, 9 years | Valuation technique, discounted cash flow | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 0.588 0.588