CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings	Common Stock Held in Treasury	Cumulative Effect, Period of Adoption, Adjustment	Total
Balance at beginning of period at Jan. 31, 2019	$ 264	$ 464,112	$ (15,194)		$ 758,881	$ (19,054)		$ 1,189,009
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity awards exercised/vested, net		(9,900)				10,016		116
Share-based compensation expense		9,349						9,349
Taxes paid for net share settlements		(7,366)						(7,366)
Other comprehensive loss, net			(1,654)					(1,654)
Repurchases of common stock						(35,216)		(35,216)
Net income (loss)					23,162			23,162
Balance at end of period (ASC 842) at Jul. 31, 2019				$ (9,580)			$ (9,580)
Balance at end of period at Jul. 31, 2019	264	456,195	(16,848)		772,463	(44,254)		1,167,820
Balance at beginning of period at Apr. 30, 2019	264	456,835	(18,421)		761,344	(13,196)		1,186,826
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity awards exercised/vested, net		(4,082)				4,158		76
Share-based compensation expense		5,122						5,122
Taxes paid for net share settlements		(1,680)						(1,680)
Other comprehensive loss, net			1,573					1,573
Repurchases of common stock						(35,216)		(35,216)
Net income (loss)					11,119			11,119
Balance at end of period (ASC 842) at Jul. 31, 2019				$ (9,580)			$ (9,580)
Balance at end of period at Jul. 31, 2019	264	456,195	(16,848)		772,463	(44,254)		1,167,820
Balance at beginning of period at Jan. 31, 2020	264	452,142	(18,008)		893,138	(36,864)		1,290,672
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity awards exercised/vested, net		(9,178)				9,358		180
Share-based compensation expense		1,737						1,737
Taxes paid for net share settlements		(317)						(317)
Other comprehensive loss, net			(252)					(252)
Net income (loss)					(54,271)			(54,271)
Balance at end of period at Jul. 31, 2020	264	444,384	(18,260)		838,867	(27,506)		1,237,749
Balance at beginning of period at Apr. 30, 2020	264	449,840	(22,034)		853,843	(35,679)		1,246,234
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity awards exercised/vested, net		(7,993)				8,173		180
Share-based compensation expense		2,548						2,548
Taxes paid for net share settlements		(11)						(11)
Other comprehensive loss, net			3,774					3,774
Net income (loss)					(14,976)			(14,976)
Balance at end of period at Jul. 31, 2020	$ 264	$ 444,384	$ (18,260)		$ 838,867	$ (27,506)		$ 1,237,749