Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Sep. 30, 2014
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)
Common stock, shares issued	63,600,000.0us-gaap_CommonStockSharesIssued	63,500,000.0us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	62,900,000.0us-gaap_CommonStockSharesOutstanding	62,900,000.0us-gaap_CommonStockSharesOutstanding
Treasury stock, shares	700,000.0us-gaap_TreasuryStockNumberOfSharesHeld	600,000.0us-gaap_TreasuryStockNumberOfSharesHeld

Face amount or stated value per share of common stock.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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

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

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Number of shares held for each class of treasury stock.

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