v3.25.1
INVESTMENT SECURITIES - Narrative (Details)
$ in Thousands
12 Months Ended
Mar. 31, 2025
USD ($)
issuer
Mar. 31, 2024
USD ($)
issuer
Defined Benefit Plan Disclosure [Line Items]    
Number of issuers | issuer 2 2
Investment securities $ 2,814,733 $ 3,905,241
Recognized impairment loss in Income Statement 406 413
Fair value of held-to-maturity 64,952  
Non-US sovereign debt    
Defined Benefit Plan Disclosure [Line Items]    
Recognized impairment loss in Income Statement 378 $ 352
Fair value of held-to-maturity 64,952  
Fair value, inputs, level 1 | Non-US sovereign debt    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of held-to-maturity 45,216  
Fair value, inputs, level 2 | Non-US sovereign debt    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of held-to-maturity $ 19,736  
Kazakhstan Sustainability Fund JSC    
Defined Benefit Plan Disclosure [Line Items]    
Percentage of trading securities (in percent) 10.00% 10.00%
Investment securities $ 578,862 $ 727,440
Ministry of Finance of the Republic of Kazakhstan    
Defined Benefit Plan Disclosure [Line Items]    
Percentage of trading securities (in percent) 10.00% 10.00%
Investment securities $ 1,527,340 $ 2,420,855