CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Common Stock Held in Treasury	Total
Balance at beginning of period at Jan. 31, 2017	$ 253	$ 437,777	$ (27,722)	$ 612,418	$ (1,490)	$ 1,021,236
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity awards exercised/vested, net	(8)	516			1,070	1,578
Share-based compensation expense		19,665				19,665
Taxes paid for net share settlements		(6,114)				(6,114)
Other comprehensive gain/loss, net			22,200			22,200
Net income				62,124		62,124
Balance at end of period at Jan. 31, 2018	245	451,844	(5,522)	674,542	(420)	1,120,689
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity awards exercised/vested, net	19	(1,595)			1,677	101
Share-based compensation expense		19,694				19,694
Taxes paid for net share settlements		(5,738)				(5,738)
Other comprehensive gain/loss, net		(93)	(9,672)			(9,765)
Other comprehensive gain/loss, net						(9,672)
Repurchases of common stock					(20,311)	(20,311)
Net income				138,067		138,067
Balance at end 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]
Cumulative effect of adoption of accounting statdard | ASC 606				(53,728)		(53,728)
Equity awards exercised/vested, net		(17,290)			17,406	116
Share-based compensation expense		17,559				17,559
Taxes paid for net share settlements		(12,239)				(12,239)
Other comprehensive gain/loss, net			(2,814)			(2,814)
Repurchases of common stock					(35,216)	(35,216)
Net income				143,837		143,837
Balance at end 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]
Cumulative effect of adoption of accounting statdard | ASC 842				$ (9,580)		$ (9,580)