Ordinary and Preference Shares - Summary of Shares Issued and Outstanding (Detail) - $ / shares	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Class Of Stock [Line Items]
Ordinary shares, shares issued	101,264,412	80,398,326
Common stock, par value
Ordinary shares, shares outstanding	101,264,412	80,398,326
Ordinary shares, par value
Preference shares, shares issued	666,665	666,665
Preference shares, shares outstanding	666,665	666,665
7% Cumulative Redeemable Preference Shares [Member]
Class Of Stock [Line Items]
Preference shares, shares issued	666,665	666,665
Liquidation amount per share	$ 32.21	$ 30.64
Preference shares, shares outstanding	666,665	666,665
Ordinary Shares [Member]
Class Of Stock [Line Items]
Ordinary shares, shares issued	101,264,412	80,398,326
Common stock, par value
Ordinary shares, shares outstanding	101,264,412	80,398,326	65,900,447	45,646,424
Ordinary shares, par value