Commitments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Sep. 30, 2011 Year Person	Sep. 30, 2010	Sep. 30, 2009
Commitments and Contingencies Disclosure [Line Items]
Contractual sublease commitments in 2012	$ 1.1
Contractual sublease commitments in 2013	1.1
Contractual sublease commitments in 2014	0.7
Rent expense under operating leases	$ 21.1	$ 22.6	$ 24.4
Number of executives in a management agreement providing for certain payments and other benefits in the event of a qualified change	23

Commitments and Contingencies Disclosure [Line Items]

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- Definition

Number Of Executives Included In Plan

+ Details

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- Definition

Operating Leases Future Minimum Payments Due In Four Years Future Minimum Sublease Rentals

+ Details

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- Definition

Operating Leases Future Minimum Payments Due In Three Years Future Minimum Sublease Rentals

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- Definition

Operating Leases Future Minimum Payments Due In Two Years Future Minimum Sublease Rentals

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- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

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