Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Voting	Additional Paid In Capital	Accumulated Other Comprehensive Income	Treasury Stock	Retained Earnings
Beginning balance, common stock (in shares) at Mar. 31, 2022		126,425,383
Beginning balance at Mar. 31, 2022	$ 2,060,395	$ 126	$ 3,023,403	$ 141	$ (1,373,840)	$ 410,565
Beginning balance, treasury stock (in shares) at Mar. 31, 2022					52,323,090
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	62,869					62,869
Unrealized net investment gains (losses)	14			14
Unrealized net gains (loss) on derivative financial instruments	(61)			(61)
Cumulative translation adjustments	(447)			(447)
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		1,758,002
Issuance of common stock pursuant to vesting of restricted stock units	2	$ 2
Stock-based compensation expense for restricted stock units granted to employees	45,068		45,068
Issuance of common stock under employee stock purchase plan (in shares)		206,029
Issuance of common stock under employee stock purchase plan	6,539		6,539
Repurchase of treasury stock (in shares)					5,104,980
Repurchase of treasury stock	(169,226)		2,856		$ (172,082)
Ending balance, common stock (in shares) at Dec. 31, 2022		128,389,414
Ending balance at Dec. 31, 2022	2,005,153	$ 128	3,077,866	(353)	$ (1,545,922)	473,434
Ending balance, treasury stock (in shares) at Dec. 31, 2022					57,428,070
Beginning balance, common stock (in shares) at Mar. 31, 2022		126,425,383
Beginning balance at Mar. 31, 2022	$ 2,060,395	$ 126	3,023,403	141	$ (1,373,840)	410,565
Beginning balance, treasury stock (in shares) at Mar. 31, 2022					52,323,090
Ending balance, common stock (in shares) at Mar. 31, 2023	71,249,045	128,683,824
Ending balance at Mar. 31, 2023	$ 2,029,649	$ 128	3,099,698	5,738	$ (1,546,128)	470,213
Ending balance, treasury stock (in shares) at Mar. 31, 2023	57,434,779				57,434,779
Beginning balance, common stock (in shares) at Sep. 30, 2022		128,373,156
Beginning balance at Sep. 30, 2022	$ 1,937,646	$ 128	3,015,644	(1,056)	$ (1,497,886)	420,816
Beginning balance, treasury stock (in shares) at Sep. 30, 2022					56,129,506
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	52,618					52,618
Unrealized net investment gains (losses)	25			25
Unrealized net gains (loss) on derivative financial instruments	564			564
Cumulative translation adjustments	114			114
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		16,258
Stock-based compensation expense for restricted stock units granted to employees	14,366		14,366
Repurchase of treasury stock (in shares)					1,298,564
Repurchase of treasury stock	(180)		47,856		$ (48,036)
Ending balance, common stock (in shares) at Dec. 31, 2022		128,389,414
Ending balance at Dec. 31, 2022	$ 2,005,153	$ 128	3,077,866	(353)	$ (1,545,922)	473,434
Ending balance, treasury stock (in shares) at Dec. 31, 2022					57,428,070
Beginning balance, common stock (in shares) at Mar. 31, 2023	71,249,045	128,683,824
Beginning balance at Mar. 31, 2023	$ 2,029,649	$ 128	3,099,698	5,738	$ (1,546,128)	470,213
Beginning balance, treasury stock (in shares) at Mar. 31, 2023	57,434,779				57,434,779
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ (115,315)					(115,315)
Unrealized net investment gains (losses)	(40)			(40)
Unrealized net gains (loss) on derivative financial instruments	26			26
Cumulative translation adjustments	146			146
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		2,028,862
Issuance of common stock pursuant to vesting of restricted stock units	3	$ 3
Stock-based compensation expense for restricted stock units granted to employees	52,579		52,579
Issuance of common stock under employee stock purchase plan (in shares)		209,791
Issuance of common stock under employee stock purchase plan	6,006		6,006
Repurchase of treasury stock (in shares)					2,467,794
Repurchase of treasury stock	$ (69,151)				$ (69,151)
Ending balance, common stock (in shares) at Dec. 31, 2023	71,019,904	130,922,477
Ending balance at Dec. 31, 2023	$ 1,903,903	$ 131	3,158,283	5,870	$ (1,615,279)	354,898
Ending balance, treasury stock (in shares) at Dec. 31, 2023	59,902,573				59,902,573
Beginning balance, common stock (in shares) at Sep. 30, 2023		130,875,398
Beginning balance at Sep. 30, 2023	$ 2,039,670	$ 130	3,142,712	5,379	$ (1,596,026)	487,475
Beginning balance, treasury stock (in shares) at Sep. 30, 2023					59,177,497
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(132,577)					(132,577)
Unrealized net investment gains (losses)	57			57
Unrealized net gains (loss) on derivative financial instruments	218			218
Cumulative translation adjustments	216			216
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		47,079
Issuance of common stock pursuant to vesting of restricted stock units	1	$ 1
Stock-based compensation expense for restricted stock units granted to employees	15,571		15,571
Repurchase of treasury stock (in shares)					725,076
Repurchase of treasury stock	$ (19,253)				$ (19,253)
Ending balance, common stock (in shares) at Dec. 31, 2023	71,019,904	130,922,477
Ending balance at Dec. 31, 2023	$ 1,903,903	$ 131	$ 3,158,283	$ 5,870	$ (1,615,279)	$ 354,898
Ending balance, treasury stock (in shares) at Dec. 31, 2023	59,902,573				59,902,573