Fair Value Of Financial Instruments (Details) $ in Millions	Sep. 30, 2018 USD ($)
Carrying Amount [Member] | Collateralized Financing Obligations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 103.1
Carrying Amount [Member] | Revolving Credit Facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	471.7
Carrying Amount [Member] | Variable Rate Term Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	227.8
Carrying Amount [Member] | Term Loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	61.1
Carrying Amount [Member] | Senior Secured Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	58.9
Carrying Amount [Member] | Asset Backed Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,066.4
Fair Value [Member] | Collateralized Financing Obligations [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	104.7
Fair Value [Member] | Term Loan [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	59.8
Fair Value [Member] | Asset Backed Notes [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,049.6
Variable Interest Entity, Primary Beneficiary [Member] | Carrying Amount [Member] | Term Loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 1.9