Basis of Preparation and Summary of Significant Accounting Policies - Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Basic Net Income Per Share
Net income	$ 136,505	$ 225,525	$ 203,009
Weighted average shares - basic	45,445	45,140	45,179
Earnings Per Share, Basic	$ 3.00	$ 5.00	$ 4.49
Diluted Net Income Per Share
Net income	$ 136,505	$ 225,525	$ 203,009
Weighted average shares - basic	45,445	45,140	45,179
Effect of dilutive securities	436	534	637
Weighted average shares - diluted	45,881,000	45,674,000	45,816,000
Earnings Per Share, Diluted	$ 2.98	$ 4.94	$ 4.43