Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Voting	Additional Paid In Capital	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Retained Earnings
Beginning balance (in shares) at Mar. 31, 2019		119,760,132			42,149,771
Beginning balance at Mar. 31, 2019	$ 2,065,433	$ 120	$ 2,828,922	$ (2,639)	$ (1,119,063)	$ 358,093
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(46,815)					(46,815)
Unrealized net investment gains (losses)	37			37
Unrealized net gain (losses) on derivative financial instruments	(11)			(11)
Cumulative translation adjustments	(1,086)			(1,086)
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		1,590,980
Issuance of common stock pursuant to vesting of restricted stock units	2	$ 2
Stock-based compensation expense for restricted stock units granted to employees	27,488		27,488
Issuance of common stock under employee stock purchase plan (in shares)		297,635
Issuance of common stock under employee stock purchase plan	6,593		6,593
Repurchase of treasury stock (in shares)					4,660,929
Repurchase of treasury stock	(111,377)				$ (111,377)
Ending balance (in shares) at Sep. 30, 2019		121,648,747			46,810,700
Ending balance at Sep. 30, 2019	1,940,264	$ 122	2,863,003	(3,699)	$ (1,230,440)	311,278
Beginning balance (in shares) at Jun. 30, 2019		120,123,018			43,568,720
Beginning balance at Jun. 30, 2019	2,011,435	$ 120	2,841,001	(3,184)	$ (1,155,252)	328,750
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(17,472)					(17,472)
Unrealized net investment gains (losses)	2			2
Unrealized net gain (losses) on derivative financial instruments	8			8
Cumulative translation adjustments	(525)			(525)
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		1,228,094
Issuance of common stock pursuant to vesting of restricted stock units	2	$ 2
Stock-based compensation expense for restricted stock units granted to employees	15,409		15,409
Issuance of common stock under employee stock purchase plan (in shares)		297,635
Issuance of common stock under employee stock purchase plan	6,593		6,593
Repurchase of treasury stock (in shares)					3,241,980
Repurchase of treasury stock	(75,188)				$ (75,188)
Ending balance (in shares) at Sep. 30, 2019		121,648,747			46,810,700
Ending balance at Sep. 30, 2019	1,940,264	$ 122	2,863,003	(3,699)	$ (1,230,440)	311,278
Beginning balance (in shares) at Mar. 31, 2020		122,006,077			49,785,171
Beginning balance at Mar. 31, 2020	1,937,919	$ 122	2,891,553	(3,160)	$ (1,305,935)	355,339
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(21,106)					(21,106)
Unrealized net investment gains (losses)	(107)			(107)
Unrealized net gain (losses) on derivative financial instruments	116			116
Cumulative translation adjustments	1,893			1,893
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		1,555,056
Issuance of common stock pursuant to vesting of restricted stock units	1	$ 1
Stock-based compensation expense for restricted stock units granted to employees	26,729		26,729
Issuance of common stock under employee stock purchase plan (in shares)		279,812
Issuance of common stock under employee stock purchase plan	6,475		6,475
Repurchase of treasury stock (in shares)					481,739
Repurchase of treasury stock	(12,600)				$ (12,600)
Ending balance (in shares) at Sep. 30, 2020		123,840,945			50,266,910
Ending balance at Sep. 30, 2020	1,939,320	$ 123	2,924,757	(1,258)	$ (1,318,535)	334,233
Beginning balance (in shares) at Jun. 30, 2020		122,353,504			49,898,334
Beginning balance at Jun. 30, 2020	1,929,817	$ 122	2,903,055	(2,241)	$ (1,309,038)	337,919
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(3,686)					(3,686)
Unrealized net investment gains (losses)	(33)			(33)
Unrealized net gain (losses) on derivative financial instruments	76			76
Cumulative translation adjustments	940			940
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		1,207,629
Issuance of common stock pursuant to vesting of restricted stock units	1	$ 1
Stock-based compensation expense for restricted stock units granted to employees	15,227		15,227
Issuance of common stock under employee stock purchase plan (in shares)		279,812
Issuance of common stock under employee stock purchase plan	6,475		6,475
Repurchase of treasury stock (in shares)					368,576
Repurchase of treasury stock	(9,497)				$ (9,497)
Ending balance (in shares) at Sep. 30, 2020		123,840,945			50,266,910
Ending balance at Sep. 30, 2020	$ 1,939,320	$ 123	$ 2,924,757	$ (1,258)	$ (1,318,535)	$ 334,233