Ordinary and Preference Shares - Summary of Shares Issued and Outstanding (Detail) - $ / shares	Jun. 30, 2016	Mar. 31, 2016
Class Of Stock [Line Items]
Common stock, shares issued	25,413,950	25,408,950
Common stock, shares outstanding	25,413,950	25,408,950
Common stock, par value
Preferred stock, shares issued	666,665	666,665
Preferred stock, shares outstanding	666,665	666,665
Ordinary Shares [Member]
Class Of Stock [Line Items]
Common stock, shares issued	25,413,950	25,408,950
Common stock, shares outstanding	25,413,950	25,408,950
Common stock, par value
7% Cumulative Redeemable Preference Shares [Member]
Class Of Stock [Line Items]
Preferred stock, shares issued	666,665	666,665
Preferred stock, shares outstanding	666,665	666,665
Liquidation amount per share	$ 24.73	$ 24.34