Summary of Significant Accounting Policies - Schedule of Earnings Per Share Basic and Diluted (Detail) - shares	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Basic weighted average shares	17,930,000	18,326,000	18,794,000
Treasury stock impact of stock options	236,000	276,000	214,000
Diluted weighted average shares	18,166,000	18,602,000	19,008,000