Securitizations and Variable Interest Entities - Schedule of Interest in Variable Interest Entity (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2013	Feb. 28, 2013
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Asset-Backed Loans Receivable, Portion Sellers Interest	$ 96.3	$ 317.3
Salus Capital Partners LLC | Unaffiliated long-term debt of consolidated variable-interest entity
Variable Interest Entity [Line Items]
VIE, consolidated carrying amount obligations	38.9	39.5
Salus Capital Partners LLC | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Asset-based loans			$ 331.1	$ 175.5
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	29.3	197.8
Variable Interest Entity, Consolidated, Carrying Amount, Asset-Backed Loans Receivable	29.3	197.8
Variable Interest Entity, Consolidated, Carrying Amount, Other Assets	13.7	85.8
Variable Interest Entity, Consolidated, Carrying Amount, Assets	43.0	283.6
VIE, consolidated carrying amount obligations	135.2	356.8
Variable Interest Entity, Consolidated, Carrying Amount, Other Liabilities	0.0	0.7
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	135.2	357.5
Salus Capital Partners LLC | Variable Interest Entity, Primary Beneficiary | Secured Debt [Member]
Variable Interest Entity [Line Items]
VIE, consolidated carrying amount obligations	0.0	219.2
Salus Capital Partners LLC | Variable Interest Entity, Primary Beneficiary | Unsecured Debt [Member]
Variable Interest Entity [Line Items]
VIE, consolidated carrying amount obligations	$ 135.2	$ 137.6