Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net income	$ 56,953	$ (26,525)	$ 62,213	$ 44,588	$ 30,428	$ 106,801
Weighted average shares – basic	45,437		45,104		45,374	45,057
Net income per share – basic	$ 1.25		$ 1.38		$ 0.67	$ 2.37
Effect of dilutive securities	456		557		483	552
Weighted average shares – diluted	45,893		45,661		45,857	45,609
Net income per share - diluted	$ 1.24		$ 1.36		$ 0.66	$ 2.34