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 at Mar. 31, 2015	$ 435,750	$ 51	$ 298,101	$ (4,645)	$ (169,516)	$ 311,759
Beginning Balance (in shares) at Mar. 31, 2015		50,812,548			10,004,743
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(28,369)					(28,369)
Unrealized net investment gains (losses)	3			3
Unrealized net gains (losses) on derivative financial instruments	1,063			1,063
Cumulative translation adjustments	1,446			1,446
Recognition from actuarial net gain from pension and other post-retirement plan	632			632
Issuance of common stock pursuant to vesting of restricted stock units	1	$ 1
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		736,170
Stock-based compensation expense for restricted stock units granted to employees	26,609		26,609
Issuance of common stock under employee stock purchase plan	10,560		10,560
Issuance of common stock under employee stock purchase plan (in shares)		447,252
Repurchase of treasury stock	(311,850)				$ (311,850)
Repurchase of treasury stock (in shares)					10,402,402
Issuance of shares related to the Comms Transaction	2,305,611	$ 62	2,305,549
Issuance of shares related to the Comms Transaction (in shares)		62,499,644
Tax effect from share-based compensation awards	1,926		1,926
Ending Balance at Mar. 31, 2016	2,443,382	$ 114	2,642,745	(1,501)	$ (481,366)	283,390
Ending Balance (in shares) at Mar. 31, 2016		114,495,614			20,407,145
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	33,291					33,291
Unrealized net investment gains (losses)	(59)			(59)
Unrealized net gains (losses) on derivative financial instruments	(54)			(54)
Cumulative translation adjustments	(1,000)			(1,000)
Recognition from actuarial net gain from pension and other post-retirement plan	(858)			(858)
Issuance of common stock pursuant to vesting of restricted stock units	2	$ 2
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		950,159
Stock-based compensation expense for restricted stock units granted to employees	36,449		36,449
Issuance of common stock under employee stock purchase plan	15,697		15,697
Issuance of common stock under employee stock purchase plan (in shares)		471,658
Repurchase of treasury stock	(89,555)				$ (89,555)
Repurchase of treasury stock (in shares)					3,468,998
Tax effect from share-based compensation awards	(1,045)		(1,045)
Ending Balance at Mar. 31, 2017	2,436,250	$ 116	2,693,846	(3,472)	$ (570,921)	316,681
Ending Balance (in shares) at Mar. 31, 2017		115,917,431			23,876,143
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	79,812					79,812
Unrealized net investment gains (losses)	(6)			(6)
Unrealized net gains (losses) on derivative financial instruments	131			131
Cumulative translation adjustments	4,889			4,889
Recognition from actuarial net gain from pension and other post-retirement plan	1,353			1,353
Issuance of common stock pursuant to vesting of restricted stock units	1	$ 1
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		1,216,535
Stock-based compensation expense for restricted stock units granted to employees	43,425		43,425
Issuance of common stock under employee stock purchase plan	17,849		17,849
Issuance of common stock under employee stock purchase plan (in shares)		610,947
Repurchase of treasury stock	(514,922)		(90,000)		$ (424,922)
Repurchase of treasury stock (in shares)					13,598,747
Ending Balance at Mar. 31, 2018	$ 2,068,782	$ 117	$ 2,665,120	$ 2,895	$ (995,843)	$ 396,493
Ending Balance (in shares) at Mar. 31, 2018		117,744,913			37,474,890