Transaction Revenue - Summary of Transaction Revenue Split By Nature (Detail) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Transaction revenue	$ 1,893.6	$ 1,546.3	$ 1,323.1
Cross Border Sevices [Member]
Disaggregation of Revenue [Line Items]
Transaction revenue	1,257.0	1,071.7	999.7
Card Services [Member]
Disaggregation of Revenue [Line Items]
Transaction revenue	391.6	280.5	207.2
Other Services [Member]
Disaggregation of Revenue [Line Items]
Transaction revenue	$ 245.0	$ 194.1	$ 116.2

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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- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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