INVESTMENT SECURITIES - Held to maturity, amortized cost to fair value (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026
Debt Securities, Available-for-sale [Line Items]
Total held-to-maturity securities	$ 521,521	$ 429,423
Gross unrecognized holding gains	14,938	26,423
Gross unrecognized holding losses	(4,462)	(6,181)
Fair value of held-to-maturity	531,997	449,665
Corporate debt
Debt Securities, Available-for-sale [Line Items]
Total held-to-maturity securities	35,326
Gross unrecognized holding gains	2,949
Gross unrecognized holding losses	0
Fair value of held-to-maturity	38,275
Non-US sovereign debt
Debt Securities, Available-for-sale [Line Items]
Total held-to-maturity securities	486,195	429,423
Gross unrecognized holding gains	11,989	26,423
Gross unrecognized holding losses	(4,462)	(6,181)
Fair value of held-to-maturity	$ 493,722	$ 449,665

Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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+ Details

- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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+ Details

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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