CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Mar. 31, 2020		27,999,000
Beginning balance at Mar. 31, 2020	$ 1,140,120	$ 280	$ 191,451	$ 973,948	$ (25,559)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (in shares)		4,000
Stock-based compensation	22,695		22,695
Shares issued upon vesting (in shares)		107,000
Shares issued upon vesting	1,502	$ 1	1,501
Exercise of stock options (in shares)		107,000
Exercise of stock options	6,775	$ 1	6,774
Shares withheld for taxes	$ (19,111)		(19,111)
Repurchases of common stock (Note 10) (in shares)	(307,080)	(307,000)
Repurchases of common stock (Note 10)	$ (99,147)	$ (3)		(99,144)
Net income	382,575			382,575
Total other comprehensive income (loss)	8,816				8,816
Ending balance (in shares) at Mar. 31, 2021		27,910,000
Ending balance at Mar. 31, 2021	1,444,225	$ 279	203,310	1,257,379	(16,743)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (in shares)		4,000
Stock-based compensation	26,780		26,780
Shares issued upon vesting (in shares)		83,000
Shares issued upon vesting	1,991	$ 1	1,990
Exercise of stock options (in shares)		29,000
Exercise of stock options	1,204		1,204
Shares withheld for taxes	$ (22,459)		(22,459)
Repurchases of common stock (Note 10) (in shares)	(1,043,554)	(1,044,000)
Repurchases of common stock (Note 10)	$ (356,653)	$ (10)		(356,643)
Net income	451,949			451,949
Total other comprehensive income (loss)	(8,212)				(8,212)
Ending balance (in shares) at Mar. 31, 2022		26,982,000
Ending balance at Mar. 31, 2022	1,538,825	$ 270	210,825	1,352,685	(24,955)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (in shares)		5,000
Stock-based compensation	26,858		26,858
Shares issued upon vesting (in shares)		53,000
Shares issued upon vesting	2,170	$ 0	2,170
Exercise of stock options (in shares)		64,000
Exercise of stock options	4,396		4,396
Shares withheld for taxes	$ (11,317)		(11,317)
Repurchases of common stock (Note 10) (in shares)	(928,262)	(928,000)
Repurchases of common stock (Note 10)	$ (297,372)	$ (8)		(297,364)
Excise taxes related to repurchases of common stock	(569)			(569)
Net income	516,822			516,822
Total other comprehensive income (loss)	(14,080)				(14,080)
Ending balance (in shares) at Mar. 31, 2023		26,176,000
Ending balance at Mar. 31, 2023	$ 1,765,733	$ 262	$ 232,932	$ 1,571,574	$ (39,035)