STOCKHOLDERS' EQUITY - Restricted Stock (Details) - $ / shares	12 Months Ended
Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Restricted Stock Units (RSUs)
Awards Outstanding
Unvested, beginning balance	281,825	327,014	435,102
Granted	142,594	137,723	52,891
Vested	(168,781)	(159,663)	(150,588)
Canceled	(12,695)	(23,249)	(10,391)
Unvested, ending balance	242,943	281,825	327,014
Weighted Average Grant Date Fair Value
Unvested, beginning balance	$ 34.56	$ 30.59	$ 30.36
Granted	37.74	38.32	26.83
Vested	32.32	30.38	28.75
Canceled	35.09	29.69	28.42
Unvested, ending balance	$ 37.95	$ 34.56	$ 30.59
Performance Shares [Member]
Awards Outstanding
Unvested, beginning balance	1,539,794	1,445,563	1,599,472
Granted	332,651	391,530	190,875
Vested	(810,655)	(292,266)	(344,784)
Canceled	(3,080)	(5,033)
Unvested, ending balance	1,058,710	1,539,794	1,445,563
Weighted Average Grant Date Fair Value
Unvested, beginning balance	$ 30.15	$ 29.26	$ 30.32
Granted	35.77	30.23	13.36
Vested	24.58	25.91	25.35
Canceled	42.41	27.10
Unvested, ending balance	$ 36.15	$ 30.15	$ 29.26

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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-Publisher FASB
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-Topic 718
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-Paragraph 2
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

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-Publisher FASB
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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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-Publisher FASB
-Name Accounting Standards Codification
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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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