Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash Flows From Operating Activities:
Net income	$ 188,044	$ 170,077	$ 146,255
Adjustments to reconcile cash provided by operating activities:
Provision for credit losses	28,956	10,037	(12,164)
Depreciation	4,145	4,437	5,139
Amortization	5,904	6,643	4,521
Loss on retirement of property and equipment	28	65	100
Loss on impairment of software	0	1,362	0
Provision for deferred income taxes	15,309	13,863	17,740
Stock-based compensation	1,881	4,127	6,805
Change in operating assets and liabilities:
Increase (decrease) in accounts payable and accrued liabilities	20,737	(730)	(4,029)
Decrease (increase) in income taxes receivable	11,496	(8,046)	(3,956)
Increase (decrease) in income taxes payable	1,493	0	(881)
(Increase) decrease in other assets	(2,345)	(1,137)	831
Net cash provided by operating activities	275,648	200,698	160,361
Cash Flows From Investing Activities:
(Increase) decrease in restricted cash and cash equivalents	(38,143)	15,920	(2,123)
Purchases of restricted securities available for sale	(532)	(1,063)	(1,451)
Proceeds from sale of restricted securities available for sale	76	2,111	0
Maturities of restricted securities available for sale	454	1,256	1,661
Principal collected on Loans receivable	996,927	785,947	661,246
Advances to Dealer-Partners	(1,152,537)	(786,909)	(516,093)
Purchases of Consumer Loans	(122,197)	(100,430)	(103,283)
Accelerated payments of Dealer Holdback	(47,411)	(32,629)	(17,372)
Payments of Dealer Holdback	(85,184)	(44,220)	(44,269)
Net decrease (increase) in other loans	886	207	(152)
Purchases of property and equipment	(6,334)	(3,440)	(2,925)
Net cash used in investing activities	(453,995)	(163,250)	(24,761)
Cash Flows From Financing Activities:
Borrowings under revolving secured line of credit	2,384,900	1,097,900	630,900
Repayments under revolving secured line of credit	(2,477,700)	(1,058,500)	(594,900)
Proceeds from secured financing	1,164,500	327,700	397,000
Repayments of secured financing	(865,319)	(432,197)	(566,578)
Principal payments under mortgage note and capital lease obligations	(235)	(559)	(1,157)
Proceeds from sale of senior notes	106,000	243,738	0
Payments of debt issuance costs	(8,370)	(15,171)	(7,581)
Repurchase of common stock	(130,886)	(202,247)	(541)
Proceeds from stock options exercised	2,921	2,903	1,941
Tax benefits from stock-based compensation plans	3,401	610	4,341
Net cash provided by (used in) financing activities	179,212	(35,823)	(136,575)
Effect of exchange rate changes on cash	0	(3)	(9)
Net increase (decrease) in cash and cash equivalents	865	1,622	(984)
Cash and cash equivalents, beginning of period	3,792	2,170	3,154
Cash and cash equivalents, end of period	4,657	3,792	2,170
Supplemental Disclosure of Cash Flow Information:
Cash paid during the period for interest	51,360	42,548	27,559
Cash paid during the period for income taxes	$ 76,458	$ 81,750	$ 67,563