Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	$ 1,186,826	$ 1,082,924	$ 1,189,009	$ 1,120,689
Equity awards exercised/vested, net	76		116	56
Share-based compensation expense	5,122	5,666	9,349	9,440
Taxes paid for net share settlements	(1,680)	(13)	(7,366)	(1,098)
Other comprehensive loss (gain), net	1,573	(11,501)	(1,654)	(8,065)
Repurchases of common stock	(35,216)		(35,216)
Other comprehensive gain (loss), net		(11,437)		(8,104)
Net income	11,119	10,077	23,162	19,962
Balance at end of period	1,167,820	1,087,217	1,167,820	1,087,217
ASU 2016-02
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption of ASC			(9,580)
ASU 2014-09
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption of ASC				(53,728)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	264	262	264	245
Equity awards exercised/vested, net		1		18
Balance at end of period	264	263	264	263
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	456,835	454,398	464,112	451,844
Equity awards exercised/vested, net	(4,082)	(51)	(9,900)	(149)
Share-based compensation expense	5,122	5,666	9,349	9,440
Taxes paid for net share settlements	(1,680)	(13)	(7,366)	(1,098)
Other comprehensive gain (loss), net				(37)
Balance at end of period	456,195	460,000	456,195	460,000
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	(18,421)	(2,086)	(15,194)	(5,522)
Other comprehensive loss (gain), net	1,573		(1,654)
Other comprehensive gain (loss), net		(11,501)		(8,065)
Balance at end of period	(16,848)	(13,587)	(16,848)	(13,587)
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	761,344	630,633	758,881	674,542
Other comprehensive gain (loss), net		64		(2)
Net income	11,119	10,077	23,162	19,962
Balance at end of period	772,463	640,774	772,463	640,774
Retained Earnings | ASU 2016-02
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption of ASC			(9,580)
Retained Earnings | ASU 2014-09
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption of ASC				(53,728)
Common Stock Held in Treasury
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	(13,196)	(283)	(19,054)	(420)
Equity awards exercised/vested, net	4,158	50	10,016	187
Repurchases of common stock	(35,216)		(35,216)
Balance at end of period	$ (44,254)	$ (233)	$ (44,254)	$ (233)