v3.26.1
INVESTMENT SECURITIES - Schedule of valuation techniques and significant level 3 inputs used in the valuation (Details)
$ in Thousands
 3 Months Ended 12 Months Ended
Jun. 30, 2026
USD ($)
Mar. 31, 2026
USD ($)
times
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Investment securities $ 2,974,677 $ 2,339,100
Significant Unobservable Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Investment securities 23,415 22,275
Discounted cash flow | Significant Unobservable Units | Corporate Equity, 4 Years, Tranche 1    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Investment securities $ 19,895  
Estimated number of years 4 years  
Discounted cash flow | Significant Unobservable Units | Corporate Equity, 4 Years, Tranche 1 | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 0.0943  
Discounted cash flow | Significant Unobservable Units | Corporate Equity, 4 Years, Tranche 1 | Termination multiplier    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 10.5  
Discounted cash flow | Significant Unobservable Units | Corporate Equity, 4 years, Tranche 2    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Investment securities $ 2,310  
Estimated number of years 4 years  
Discounted cash flow | Significant Unobservable Units | Corporate Equity, 4 years, Tranche 2 | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 0.1011  
Discounted cash flow | Significant Unobservable Units | Corporate Equity, 4 years, Tranche 2 | Termination multiplier    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 0.935  
Discounted cash flow | Significant Unobservable Units | Corporate equity, 3 years    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Investment securities   $ 18,840
Estimated number of years   3 years
Discounted cash flow | Significant Unobservable Units | Corporate equity, 3 years | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input   0.090
Discounted cash flow | Significant Unobservable Units | Corporate equity, 3 years | Termination multiplier    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input | times   10.5
Discounted cash flow | Significant Unobservable Units | Corporate Equity, 6 Years    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Investment securities   $ 2,223
Estimated number of years   6 years
Discounted cash flow | Significant Unobservable Units | Corporate Equity, 6 Years | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input   0.1036
Discounted cash flow | Significant Unobservable Units | Corporate Equity, 6 Years | Termination multiplier    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input | times   0.935
Discounted cash flow | Significant Unobservable Units | Corporate debt, 2 years    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Investment securities $ 1,077 $ 1,078
Estimated number of years 2 years 2 years
Discounted cash flow | Significant Unobservable Units | Corporate debt, 2 years | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 0.132 0.132
Discounted cash flow | Significant Unobservable Units | Corporate equity, 9 years    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Investment securities $ 133 $ 134
Estimated number of years 9 years 9 years
Discounted cash flow | Significant Unobservable Units | Corporate equity, 9 years | Discount rate    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Measurement input 0.588 0.588