Earnings Per Common Share (Computation Of Basic And Diluted Earnings Per Common Share) (Details) (USD $) In Millions, except Per Share data	3 Months Ended	12 Months Ended
Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2009
Earnings Per Common Share
Net income attributable to Carpenter									$ 71.0	$ 2.1	$ 47.9
Less: earnings and dividends allocated to participating securities									(0.8)	(0.2)	(0.1)
Earnings available for Carpenter common shareholders									$ 70.2	$ 1.9	$ 47.8
Weighted average common shares outstanding, basic	44.2	44.1	44.1	44.1	44.0	44.0	44.0	43.9	44.1	43.9	43.9
Effect of shares issuable under share based compensation plans									0.6	0.5	0.3
Weighted average number of common shares outstanding, diluted	45.0	44.7	44.7	44.5	44.5	44.4	44.2	43.9	44.7	44.4	44.2
Basic earnings per common share									$ 1.59	$ 0.04	$ 1.08
Diluted earnings per common share									$ 1.59	$ 0.04	$ 1.08

The portion of profit or loss for the period which is attributable to the parent.

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Participating Securities Distributed And Undistributed Earnings

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The amount of income (loss) from continuing operations per each share of common stock outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Number 128
-Paragraph 36, 37, 38

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The amount of income (loss) from continuing operations available to each share of common stock outstanding during the reporting period and each share that would have been outstanding assuming the issuance of common shares for all dilutive potential common shares outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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-Paragraph 21
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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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The sum of dilutive potential common shares used in the calculation of the diluted per-share computation.

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The average number of shares issued and outstanding that are used in calculating diluted EPS, determined based on the timing of issuance of shares in the period.

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Number of [basic] shares, after adjustment for contingently issuable shares and other shares not deemed outstanding, determined by relating the portion of time within a reporting period that common shares have been outstanding to the total time in that period.

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