Commitments and Contingencies (Other Disclosures) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Jun. 30, 2012	Mar. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Commitments and Contingencies Disclosure [Abstract]
Operating leases, rent expense, net				$ 2.3	$ 2.7	$ 2.7
Fair value assumptions, credit adjusted risk-free rate, range minimal amount				3.25%
Fair value assumptions, credit adjusted risk-free rate, range maximum amount				5.78%
Asset retirement obligation, liabilities settled				0.1
Asset retirement obligation, accretion expense				0.2	0.2	0
Business combination, indemnification assets, range of outcomes, value (up to $3.4 million)	3.4
Business combination, indemnification duration, period taken into account for	2 years
Business combination, indemnification assets, amount as of acquisition date (up to $1.5 million)				1.5
Litigation settlement, expense		1.0
Proceeds from legal settlements			$ 2.6