Declaration of Dividend Payable - Additional Information (Detail) - $ / shares		3 Months Ended
May 16, 2018	Jul. 31, 2018	Jul. 31, 2017
Dividends [Abstract]
Cash dividends declared per common share	$ 0.11	$ 0.11	$ 0.11
Cash dividend payable date		Aug. 31, 2018
Cash dividends declared, record date		Aug. 17, 2018
Cash dividends payable, declared date		May 16, 2018

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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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- References

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- Definition

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

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- Definition

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

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No definition available.

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