Stock-Based Compensation and Stock Options - Stock Compensation Expense for Time Based Options and Performance Based Options (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Effect on basic earnings per share	$ 0.78	$ 0.64	$ 2.62	$ 1.76
Effect on diluted earnings per share	$ 0.76	$ 0.63	$ 2.57	$ 1.74
Time Based Options and Performance Based Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total cost of stock-based compensation included in income before income tax provision	$ 1,183,000	$ 1,251,000	$ 3,884,000	$ 3,484,000
Amount of income tax benefit recognized	(256,000)	(231,000)	(765,000)	(724,000)
Amount charged against net income	$ 927,000	$ 1,020,000	$ 3,119,000	$ 2,760,000
Effect on basic earnings per share	$ (0.05)	$ (0.06)	$ (0.17)	$ (0.15)
Effect on diluted earnings per share	$ (0.05)	$ (0.06)	$ (0.17)	$ (0.15)
Time Based Options and Performance Based Options [Member] | Cost of Revenues [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total cost of stock-based compensation included in income before income tax provision	$ 487,000	$ 516,000	$ 1,539,000	$ 1,510,000
Time Based Options and Performance Based Options [Member] | General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total cost of stock-based compensation included in income before income tax provision	$ 696,000	$ 735,000	$ 2,345,000	$ 1,974,000