Weighted Average Shares and Net Income Per Share - Additional Information (Detail) - shares	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Basic weighted average common and common equivalent shares outstanding	18,759,000	19,581,000	18,785,000	19,577,000
Diluted weighted average common and common equivalent shares outstanding	18,966,000	19,733,000	18,983,000	19,743,000