Total Options Outstanding, Range Of Exercise Prices and Remaining Contractual Lives (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
Nov. 30, 2012
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
No. of Options	1,304
Weighted Average Exercise Price	$ 20.09
Weighted Average Remaining Life	3 years 10 months 24 days
$0.00 to $3.21
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Prices, Lower limit	$ 0.00
Range of Prices, Upper limit	$ 3.21
$3.22 to $6.41
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Prices, Lower limit	$ 3.22
Range of Prices, Upper limit	$ 6.41
No. of Options	2
Weighted Average Exercise Price	$ 4.13
Weighted Average Remaining Life	7 months 6 days
$6.42 to $9.62
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Prices, Lower limit	$ 6.42
Range of Prices, Upper limit	$ 9.62
No. of Options	207
Weighted Average Exercise Price	$ 8.62
Weighted Average Remaining Life	2 years 2 months 12 days
$9.63 to $12.82
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Prices, Lower limit	$ 9.63
Range of Prices, Upper limit	$ 12.82
No. of Options	157
Weighted Average Exercise Price	$ 11.10
Weighted Average Remaining Life	3 years 2 months 12 days
$12.83 to $16.03
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Prices, Lower limit	$ 12.83
Range of Prices, Upper limit	$ 16.03
No. of Options	363
Weighted Average Exercise Price	$ 14.69
Weighted Average Remaining Life	3 years 7 months 6 days
$16.04 to $32.05
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Prices, Lower limit	$ 16.04
Range of Prices, Upper limit	$ 32.05
No. of Options	575
Weighted Average Exercise Price	$ 30.14
Weighted Average Remaining Life	4 years 10 months 24 days

Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a, b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

+ Details

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- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

+ Details

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