Aggregate dividends declared during the period for each share of common stock outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

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The per share amount of a dividend declared, but not paid, as of the financial reporting date.

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Date the dividend to be paid was declared, in CCYY-MM-DD format.

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Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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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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Stockholders' Equity Dividends Declared (Details) - $ / shares	3 Months Ended	12 Months Ended
	Apr. 30, 2018	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016	Feb. 15, 2018
Dividends Payable [Line Items]
Common Stock, Dividends, Per Share, Declared		$ 1.95	$ 1.75	$ 1.58
Subsequent Event [Member]
Dividends Payable [Line Items]
Dividends Payable, Date of Record	Mar. 20, 2018
Dividends Payable, Date Declared	Feb. 15, 2018
Dividends Payable, Date to be Paid	Apr. 10, 2018
Dividends Payable, Amount Per Share					$ 0.50