Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash Flows From Operating Activities:
Net income	$ 49.8	$ 60.6
Adjustments to reconcile cash provided by operating activities:
Provision for credit losses	4.7	5.8
Depreciation	1.3	1.4
Amortization	1.7	1.8
Provision (benefit) for deferred income taxes	27.7	(11.0)
Loss on extinguishment of debt	21.8
Stock-based compensation	4.4	1.5
Change in operating assets and liabilities:
Decrease in accounts payable and accrued liabilities	(2.4)	(0.6)
(Increase) decrease in income taxes receivable	(0.9)	0.5
(Decrease) increase in income taxes payable	(15.7)	18.7
Decrease in other assets	1.1	2.2
Net cash provided by operating activities	93.5	80.9
Cash Flows From Investing Activities:
Increase in restricted cash and cash equivalents	(35.3)	(23.9)
Purchases of restricted securities available for sale	(15.2)	(21.8)
Proceeds from sale of restricted securities available for sale	2.1	4.0
Maturities of restricted securities available for sale	14.5	16.4
Principal collected on Loans receivable	408.7	345.5
Advances to Dealers	(421.3)	(378.6)
Purchases of Consumer Loans	(51.1)	(27.9)
Accelerated payments of Dealer Holdback	(11.2)	(9.5)
Payments of Dealer Holdback	(34.5)	(30.0)
Net increase in other loans	(0.5)	(0.4)
Purchases of property and equipment	(2.1)	(1.2)
Net cash used in investing activities	(145.9)	(127.4)
Cash Flows From Financing Activities:
Borrowings under revolving secured line of credit	525.1	595.2
Repayments under revolving secured line of credit	(512.0)	(522.8)
Proceeds from secured financing	360.6	312.6
Repayments of secured financing	(157.6)	(279.8)
Proceeds from issuance of senior notes	300.0
Repayment of senior notes	(350.0)
Principal payments under mortgage note	(0.1)
Payments of debt issuance costs and debt extinguishment costs	(22.8)	(0.4)
Repurchase of common stock	(103.6)	(59.7)
Proceeds from stock options exercised	0.6
Tax benefits from stock-based compensation plans	13.6	0.2
Net cash provided by financing activities	53.8	45.3
Net increase (decrease) in cash and cash equivalents	1.4	(1.2)
Cash and cash equivalents, beginning of period	4.2	9.0
Cash and cash equivalents, end of period	5.6	7.8
Supplemental Disclosure of Cash Flow Information:
Cash paid during the period for interest	23.8	22.2
Cash paid during the period for income taxes	$ 5.5	$ 25.7