Increasing or Decreasing Current Health Care Cost Trend (Detail) - USD ($) $ in Thousands	12 Months Ended
May 31, 2017	May 31, 2016
Postretirement Benefits, U.S. Plans
Assumed Health Care Cost Trend Rates, Effect of One Percentage Point Change [Line Items]
1% Increase in trend rate, accumulated benefit obligation	$ 229	$ 313
1% Increase in trend rate, postretirement cost	9	11
1% Decrease in trend rate, accumulated benefit obligation	(201)	(272)
1% Decrease in trend rate, postretirement cost	(8)	(9)
Postretirement Benefits, Non-U.S. Plans
Assumed Health Care Cost Trend Rates, Effect of One Percentage Point Change [Line Items]
1% Increase in trend rate, accumulated benefit obligation	6,410	5,552
1% Increase in trend rate, postretirement cost	547	504
1% Decrease in trend rate, accumulated benefit obligation	(5,016)	(4,289)
1% Decrease in trend rate, postretirement cost	$ (406)	$ (383)

Assumed Health Care Cost Trend Rates, Effect of One Percentage Point Change [Line Items]

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- Definition

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (m)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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- Definition

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

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The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

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