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, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Effect on basic earnings per share	$ 0.98	$ 0.78	$ 2.77	$ 2.62
Effect on diluted earnings per share	$ 0.96	$ 0.76	$ 2.73	$ 2.57
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	$ 1,698,000	$ 1,183,000	$ 4,027,000	$ 3,884,000
Amount of income tax benefit recognized	(410,000)	(256,000)	(895,000)	(765,000)
Amount charged against net income	$ 1,288,000	$ 927,000	$ 3,132,000	$ 3,119,000
Effect on basic earnings per share	$ (0.07)	$ (0.05)	$ (0.18)	$ (0.17)
Effect on diluted earnings per share	$ (0.07)	$ (0.05)	$ (0.18)	$ (0.17)
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	$ 670,000	$ 487,000	$ 1,879,000	$ 1,539,000
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	$ 1,028,000	$ 696,000	$ 2,148,000	$ 2,345,000