Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash Flows From Operating Activities:
Net income (loss)	$ 202.1	$ (83.8)
Adjustments to reconcile cash provided by operating activities:
Provision for credit losses	21.3	354.7
Depreciation	2.4	1.8
Amortization	4.1	3.7
Provision (benefit) for deferred income taxes	12.9	(37.5)
Stock-based compensation	1.1	1.8
Loss on extinguishment of debt	0.0	7.4
Other	(0.1)	(0.2)
Change in operating assets and liabilities:
Decrease in accounts payable and accrued liabilities	24.0	(35.5)
Decrease in income taxes receivable	48.7	6.6
Decrease in other assets	8.7	12.3
Net cash provided by operating activities	325.2	231.3
Cash Flows From Investing Activities:
Purchases of restricted securities available for sale	(11.8)	(16.0)
Proceeds from sale of restricted securities available for sale	5.2	8.1
Maturities of restricted securities available for sale	3.5	4.0
Principal collected on Loans receivable	973.0	815.3
Advances to Dealers	(647.1)	(638.1)
Purchases of Consumer Loans	(385.2)	(417.2)
Accelerated payments of Dealer Holdback	(10.4)	(11.4)
Payments of Dealer Holdback	(39.0)	(36.6)
Purchases of property and equipment	(0.8)	(4.4)
Net cash used in investing activities	(112.6)	(296.3)
Cash Flows From Financing Activities:
Borrowings under revolving secured line of credit	807.6	1,121.8
Repayments under revolving secured line of credit	(903.5)	(1,041.9)
Proceeds from secured financing	728.8	1,115.9
Repayments of secured financing	(521.3)	(497.1)
Proceeds from issuance of senior notes	0.0	0.0
Repayment of senior notes	0.0	401.8
Payments of debt issuance costs and debt extinguishment costs	(7.6)	(8.5)
Repurchase of common stock	(135.2)	(307.1)
Other	6.6	(0.2)
Net cash used by financing activities	(24.6)	(18.9)
Net increase (decrease) in cash and cash equivalents and restricted cash and cash equivalents	188.0	(83.9)
Cash and cash equivalents and restricted cash and cash equivalents beginning of period	396.2	517.7
Cash and cash equivalents and restricted cash and cash equivalents end of period	584.2	433.8
Supplemental Disclosure of Cash Flow Information:
Cash paid during the period for interest	41.5	58.2
Cash paid during the period for income taxes	$ 0.0	$ 0.8