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Purchase of Treasury Stock - Additional Information (Detail) - USD ($)
12 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Mar. 31, 2016
Jan. 29, 2015
Equity [Abstract]        
Stock repurchase program authorized amount       $ 18,000,000
Number of shares purchased during period 0 0 539,000  
Aggregate cost of shares purchased during period $ 119,000 $ 29,000 $ 9,441,000