Intangible Assets - Gross and Net Intangible Assets by Major Class (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Sep. 30, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 19.3	$ 16.2
Finite-Lived Intangible Assets, Accumulated Amortization	(7.9)	(6.3)
Finite-Lived Intangible Assets, Net	11.4	9.9
Noncompete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Noncompete Agreements, Gross	3.7	3.7
Finite-Lived Intangible Assets, Accumulated Amortization	(3.7)	(3.0)
Finite-Lived Intangible Assets, Net	0	0.7
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Trade Names, Gross	0.7	0.7
Finite-Lived Intangible Assets, Accumulated Amortization	(0.6)	(0.5)
Finite-Lived Intangible Assets, Net	0.1	0.2
Computer Software, Intangible Asset [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Computer Software, Gross	2.2	2.2
Finite-Lived Intangible Assets, Accumulated Amortization	(1.4)	(1.0)
Finite-Lived Intangible Assets, Net	0.8	1.2
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Customer Lists, Gross	12.7	9.6
Finite-Lived Intangible Assets, Accumulated Amortization	(2.2)	(1.8)
Finite-Lived Intangible Assets, Net	$ 10.5	$ 7.8