Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Paragraph 2
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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
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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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

Percentage of vesting of share-based compensation awards.

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-Publisher FASB
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Equity Incentive Plans - Restricted Stock (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017	Mar. 31, 2018	Jan. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 53,654	$ 36,838	$ 97,609	$ 69,057
Compensation cost, weighted average term			2 years 1 month 6 days
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award balance (in shares)	19,315,886		19,315,886		1,375,210	17,682,646
Issued (in shares)			7,751,921
Compensation cost, weighted average term			3 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 6,700		$ 10,200
Unrecognized stock-based compensation expense	$ 31,700		$ 31,700
Compensation cost, weighted average term			2 years 7 months 6 days
Restricted Stock \| Performance Vesting Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award balance (in shares)					697,116
Restricted Stock \| Service Vesting Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award balance (in shares)					678,094
Restricted Stock \| Performance Vesting At Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issued (in shares)	21,047		1,954,908
Restricted Stock \| Maximum \| Performance Vesting At Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage			180.00%
Restricted Stock \| Minimum \| Performance Vesting At Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage			0.00%