Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash Flows From Operating Activities:
Net income	$ 106,851	$ 88,035
Adjustments to reconcile cash provided by operating activities:
Provision for credit losses	7,957	17,844
Depreciation	2,487	2,040
Amortization	3,330	2,773
Loss on retirement of property and equipment	10	13
Provision for deferred income taxes	10,990	671
Stock-based compensation	4,556	1,192
Change in operating assets and liabilities:
Increase in accounts payable and accrued liabilities	9,867	21,077
(Increase) decrease in income taxes receivable	(18)	9,278
Increase in income taxes payable	4,408
Decrease (increase) in other assets	1,141	(2,964)
Net cash provided by operating activities	151,579	139,959
Cash Flows From Investing Activities:
Increase in restricted cash and cash equivalents	(23,703)	(19,560)
Purchases of restricted securities available for sale	(100)	(303)
Proceeds from sale of restricted securities available for sale	45
Maturities of restricted securities available for sale		380
Principal collected on Loans receivable	597,598	494,412
Advances to Dealers	(675,346)	(610,207)
Purchases of Consumer Loans	(60,754)	(63,495)
Accelerated payments of Dealer Holdback	(24,223)	(24,416)
Payments of Dealer Holdback	(62,616)	(34,749)
Net decrease in other loans	68	538
Purchases of property and equipment	(6,009)	(2,569)
Net cash used in investing activities	(255,040)	(259,969)
Cash Flows From Financing Activities:
Borrowings under revolving secured line of credit	1,262,600	1,112,200
Repayments under revolving secured line of credit	(1,293,400)	(1,121,700)
Proceeds from secured financing	922,650	295,000
Repayments of secured financing	(757,481)	(142,435)
Principal payments under mortgage note and capital lease obligations	(122)	(116)
Proceeds from sale of senior notes		106,000
Payments of debt issuance costs	(3,731)	(5,164)
Repurchase of common stock	(28,465)	(126,675)
Proceeds from stock options exercised	345	2,473
Tax benefits from stock-based compensation plans	1,558	2,325
Net cash provided by financing activities	103,954	121,908
Net increase in cash and cash equivalents	493	1,898
Cash and cash equivalents, beginning of period	4,657	3,792
Cash and cash equivalents, end of period	5,150	5,690
Supplemental Disclosure of Cash Flow Information:
Cash paid during the period for interest	27,567	24,690
Cash paid during the period for income taxes	44,094	38,030
Supplemental Disclosure of Non-Cash Transactions
Repurchase of common stock during the period and settled after June 30, 2012	$ 84,450