Assets and Liabilities, at Fair Value - Contingent Consideration (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Sep. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Payments to Acquire Businesses, Gross			$ 3.4
Equity Investments in Exchange Stock - Fair Value	$ 5.6		5.6		$ 4.8
Equity Investments in Exchange Stock - Cost	3.7		3.7		$ 3.7
Change in fair value of contingent consideration for acquisitions	0.2	$ (0.2)	1.9	$ 0.6
Contingent Consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in fair value of contingent consideration for acquisitions			0.4	0.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)	$ 0.2	$ (0.2)	$ 0.4	$ 0.1