Weighted Average Shares and Net Income Per Share - Calculations of Basic and Diluted Weighted Shares (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Income	$ 6,691,000	$ 6,832,000	$ 21,859,000	$ 23,014,000
Basic:
Weighted average common shares outstanding	19,673,000	20,599,000	19,908,000	20,784,000
Net Income per share, Basic	$ 0.34	$ 0.33	$ 1.10	$ 1.11
Diluted:
Weighted average common shares outstanding	19,673,000	20,599,000	19,908,000	20,784,000
Treasury stock impact of stock options	179,000	187,000	175,000	231,000
Total common and common equivalent shares	19,852,000	20,786,000	20,083,000	21,015,000
Net Income per share, Diluted	$ 0.34	$ 0.33	$ 1.09	$ 1.10