Summary of Significant Accounting Policies $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2020 segment	Dec. 31, 2020 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of reportable segments | segment			1
Uninsured cash and cash equivalents	$ 45.2			$ 15.7
Adoption of CECL		$ 0.0
Provision for credit losses	21.3	354.7
Restricted Cash and Cash Equivalents [Member]
Summary Of Significant Accounting Policies [Line Items]
Uninsured cash and cash equivalents	535.2			$ 376.9
New Consumer Loan Assignments [Member]
Summary Of Significant Accounting Policies [Line Items]
Provision for credit losses	131.8	157.9
Loans Receivable [Member]
Summary Of Significant Accounting Policies [Line Items]
Adoption of CECL		2,463.6
Provision for credit losses	$ 0.0	$ 0.0