Guarantor Consolidating Financial Statements Guarantor Cash Flow (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Dec. 31, 2010	Sep. 30, 2010	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2010
Net Income (Loss) Attributable to Parent	$ 74,633	$ 51,300	$ 463,126	$ 385,527	$ 220,546
Depreciation, Depletion and Amortization, Nonproduction	7,809	14,649	255,182	109,619	79,044
Amortization of Deferred Loan Origination Fees, Net	1,111	(942)	(53,189)	(20,702)	4,791
Amortization of Finance Receivables Pemium	77,092		(10,419)	177,566
Amortization of Debt Discount (Premium)	(27,458)		(31,648)	(67,671)
Provision for Loan and Lease Losses	26,352	74,618	303,692	178,372	388,058
Deferred Income Tax Expense (Benefit)	21,367	452	2,626	50,236	(24,567)
Share-based Compensation		5,019	3,716	17,106	15,115
Amortization Of Warrant Costs					1,968
Non-Cash Interest Charges on Convertible Debt		5,625			21,554
Other Noncash Income (Expense)	(11,539)	(13,800)	(11,209)	(23,218)	(16,237)
Change In Equity In Income Of Affiliates
Increase (Decrease) in Income Taxes Receivable					197,402
Increase Decrease In Other Assets	(369)	16,373	2,378	34,649	5,256
Increase (Decrease) in Accounts Payable and Accrued Liabilities	(10,275)	(9,957)	47,946	(21,399)	26,245
Increase (Decrease) in Accrued Taxes Payable	(9,448)	1,405	7,816	(77,285)	9,534
Increase or Decrease in Intercompany Taxes Payable	42,214		258,316	258,092
Net Cash Provided by (Used in) Operating Activities	191,489	144,742	1,238,333	1,000,892	928,709
Principal Collection and Recoveries on Receivables	870,862	883,807	4,006,893	3,719,264	3,606,680
Principal Collections and Recoveries on Commercial Lending Receivables			667,181
Net Proceeds From the Sale of Receivables
Purchases of Leased Vehicles	(10,655)		(1,077,163)	(857,138)
Proceeds from Leases Held-for-investment			55,414	38,054
Payments to Acquire Property, Plant, and Equipment	2,429	312	13,489	8,359	1,581
Payments to Acquire Businesses, Gross				9,601
Cash Acquired from Acquisition				9,283
Increase (Decrease) in Restricted Cash and Investments	(49,860)	45,787	(190,375)	(6,799)	78,549
Increase (Decrease) in Restricted Cash	(3,030)	(8,257)	(122,345)	5,108	(52,354)
Payments for (Proceeds from) Other Investing Activities	(13,236)	(40,193)	10,911	12,602	(53,922)
Investment in Affiliates - Net Change
Net Cash Provided by (Used in) Investing Activities	(23,414)	(54,605)	(2,839,606)	(2,140,047)	1,542,224
Proceeds from Lines of Credit	468,394	484,921	1,199,707	3,716,609	775,665
Repayments of Lines of Credit	(256,362)	(552,951)	1,950,484	3,446,074	(1,806,852)
Proceeds from Issuance of Financial Services Obligations	700,000	1,050,000	6,400,000	4,550,000	2,352,493
Repayments of Financial Services Obligations	(954,644)	(795,512)	4,282,977	3,675,459	(3,674,062)
Proceeds from Issuance of Senior Long-term Debt			1,000,000	500,000
Payments of Debt Issuance Costs	4,314	7,686	48,201	49,318	24,754
Extinguishment of Debt, Amount	(464,254)		(505)	(75,164)
Proceeds from Contributions from Parent
Proceeds from (Payments for) Other Financing Activities		(313)		(528)	(645)
Increase (Decrease) Due from Affiliates
Net Cash Provided by (Used in) Financing Activities	(511,180)	165,161	2,317,255	1,520,066	(2,381,655)
Cash and Cash Equivalents, Period Increase (Decrease)	(343,105)	255,298	715,982	380,911	89,278
Effect of Exchange Rate on Cash and Cash Equivalents	130	(42)	1,215	(3,168)	(292)
Cash and Cash Equivalents, at Carrying Value	194,554	537,529	1,289,494	572,297	282,273
Proceeds From Issue of Common Stock - Non-Cash		2,138			15,635
Repayments of Long-term Debt					(20,425)
Cash Settlement of Share Based Awards		(16,062)
Consumer Loans Auto Financing Receivable [Member]
Payments to Acquire Receivables	(947,318)	(940,763)	(5,556,169)	(5,020,639)	(2,090,602)
Commercial Loan [Member]
Payments to Acquire Receivables			(1,224,082)
Guarantor Subsidiaries [Member]
Net Income (Loss) Attributable to Parent	94,876	70,364	501,559	388,349	236,879
Depreciation, Depletion and Amortization, Nonproduction	338	225	1,686	1,653	1,766
Amortization of Deferred Loan Origination Fees, Net	(11)	(646)	340	(1,415)	(578)
Amortization of Finance Receivables Pemium	11,305		25	9,742
Provision for Loan and Lease Losses	11,797	56,760	231,033	157,923	166,706
Deferred Income Tax Expense (Benefit)	(48,730)	(17,521)	77,523	(1,062)	162,627
Other Noncash Income (Expense)	4,841	(787)	1,871	18,929	(3,495)
Change In Equity In Income Of Affiliates	(88,171)	(115,397)	(598,939)	(488,787)	(369,120)
Increase Decrease In Other Assets	19,127	10,603	(4,031)	58	(6,478)
Increase (Decrease) in Accounts Payable and Accrued Liabilities	(4,223)	(6,609)	32,397	28,944	8,388
Increase (Decrease) in Accrued Taxes Payable	138	6,270	(653)	4,882	(1,607)
Net Cash Provided by (Used in) Operating Activities	1,287	3,262	242,811	119,216	195,088
Principal Collection and Recoveries on Receivables	(105)	(38,671)	(1,137)	1,339	61,906
Principal Collections and Recoveries on Commercial Lending Receivables			667,181
Net Proceeds From the Sale of Receivables	1,001,126	1,155,695	4,887,966	4,802,863	1,606,156
Payments to Acquire Property, Plant, and Equipment	617	212	2,447	2,617	580
Payments for (Proceeds from) Other Investing Activities	7,330	(1,370)	(31,318)	2,840	(29,992)
Investment in Affiliates - Net Change	(1,820,204)	5,520	(2,738,205)	(791,737)	(2,155,664)
Net Cash Provided by (Used in) Investing Activities	1,865,960	171,899	1,540,835	569,843	1,762,536
Proceeds from Contributions from Parent	63,421			15,766
Increase (Decrease) Due from Affiliates	2,271,579	(77,588)	1,032,012	389,273	1,867,467
Net Cash Provided by (Used in) Financing Activities	(2,208,158)	77,588	(1,032,012)	(373,507)	(1,867,467)
Cash and Cash Equivalents, Period Increase (Decrease)	(340,911)	252,749	751,634	315,552	90,157
Cash and Cash Equivalents, at Carrying Value	185,004	525,915	1,252,190	500,556	273,166
Guarantor Subsidiaries [Member] | Consumer Loans Auto Financing Receivable [Member]
Payments to Acquire Receivables	(947,318)	(940,763)	(5,556,169)	(5,020,639)	(2,090,602)
Guarantor Subsidiaries [Member] | Commercial Loan [Member]
Payments to Acquire Receivables			(1,224,082)
Non-Guarantor Subsidiaries [Member]
Net Income (Loss) Attributable to Parent	85,766	115,762	586,583	505,188	375,319
Depreciation, Depletion and Amortization, Nonproduction	5,958	13,938	250,778	102,180	75,590
Amortization of Deferred Loan Origination Fees, Net	1,122	(296)	(53,529)	(19,287)	5,369
Amortization of Finance Receivables Pemium	65,787		(10,444)	167,824
Amortization of Debt Discount (Premium)	(27,416)		(31,648)	(67,488)
Provision for Loan and Lease Losses	14,555	17,858	72,659	20,449	221,352
Deferred Income Tax Expense (Benefit)	20,991	64,051	(65,252)	(46,723)	(268,589)
Other Noncash Income (Expense)	(16,622)	(13,013)	(13,080)	(43,583)	(12,459)
Increase (Decrease) in Income Taxes Receivable					35,366
Increase Decrease In Other Assets	(9,621)	1,685	2,782	32,695	3,793
Increase (Decrease) in Accounts Payable and Accrued Liabilities	19,780	(4,085)	12,732	(15,836)	(41,796)
Increase (Decrease) in Accrued Taxes Payable	(1,031)	(5,154)	(2,298)	(6,298)	(148)
Net Cash Provided by (Used in) Operating Activities	159,269	190,746	749,283	629,121	393,797
Principal Collection and Recoveries on Receivables	870,967	922,478	4,008,030	3,717,925	3,544,774
Purchases of Leased Vehicles	(10,655)		(1,077,163)	(857,138)
Proceeds from Leases Held-for-investment			55,414	38,054
Payments to Acquire Property, Plant, and Equipment	4,402	101	11,042	7,666	1,001
Payments to Acquire Businesses, Gross				9,601
Cash Acquired from Acquisition				9,283
Increase (Decrease) in Restricted Cash and Investments	(49,860)	45,787	(190,375)	(6,799)	78,549
Increase (Decrease) in Restricted Cash	(3,030)	(8,257)	(122,345)	5,108	(52,354)
Payments for (Proceeds from) Other Investing Activities	(20,566)	(38,823)	(3,336)	9,762	(23,930)
Net Cash Provided by (Used in) Investing Activities	(71,760)	(232,025)	(1,596,671)	(1,920,077)	1,935,352
Proceeds from Lines of Credit	468,394	484,921	1,199,707	3,716,609	775,665
Repayments of Lines of Credit	(256,362)	(552,951)	1,950,484	3,446,074	(1,806,852)
Proceeds from Issuance of Financial Services Obligations	700,000	1,050,000	6,400,000	4,550,000	2,352,493
Repayments of Financial Services Obligations			4,282,977	3,675,459	(3,674,062)
Payments of Debt Issuance Costs	4,314	7,686	35,964	41,696	26,564
Proceeds from Contributions from Parent	(1,885,434)		(2,744,846)	721,641
Increase (Decrease) Due from Affiliates	(1,842,610)	140,434	(2,219,634)	462,570	(2,209,044)
Net Cash Provided by (Used in) Financing Activities	(89,750)	43,705	805,070	1,362,451	(2,329,153)
Cash and Cash Equivalents, Period Increase (Decrease)	(2,241)	2,426	(42,318)	71,495	(4)
Effect of Exchange Rate on Cash and Cash Equivalents	177	81	7,881	(9,304)	(1,167)
Cash and Cash Equivalents, at Carrying Value	9,550	11,614	37,304	71,741	9,107
Proceeds From Issue of Common Stock - Non-Cash		5,367			(2,158,877)
Non-Guarantor Subsidiaries [Member] | Consumer Loans Auto Financing Receivable [Member]
Payments to Acquire Receivables	(1,001,126)	(1,155,695)	(4,887,966)	(4,802,863)	(1,606,156)
Consolidation, Eliminations [Member]
Net Income (Loss) Attributable to Parent	(180,642)	(186,126)	(1,088,142)	(893,537)	(612,198)
Change In Equity In Income Of Affiliates	180,642	186,126	1,088,142	893,537	612,198
Net Cash Provided by (Used in) Operating Activities
Net Proceeds From the Sale of Receivables	(1,001,126)	(1,155,695)	(4,887,966)	(4,802,863)	(1,606,156)
Investment in Affiliates - Net Change	1,788,448	(7,596)	2,738,205	784,551	2,146,356
Net Cash Provided by (Used in) Investing Activities	(1,788,448)	7,596	(2,738,205)	(784,551)	(2,146,356)
Proceeds from Contributions from Parent	1,822,013		2,744,846	(737,407)
Increase (Decrease) Due from Affiliates	31,699	51	(25)	(1,504,841)	5,166
Net Cash Provided by (Used in) Financing Activities	1,790,314	(5,418)	2,744,871	767,434	2,153,711
Cash and Cash Equivalents, Period Increase (Decrease)	1,866	2,178	6,666	(17,117)	7,355
Effect of Exchange Rate on Cash and Cash Equivalents	(1,866)	(2,178)	(6,666)	17,117	(7,355)
Proceeds From Issue of Common Stock - Non-Cash		(5,367)			2,158,877
Consolidation, Eliminations [Member] | Consumer Loans Auto Financing Receivable [Member]
Payments to Acquire Receivables	1,001,126	1,155,695	4,887,966	4,802,863	1,606,156
Parent Company [Member]
Net Income (Loss) Attributable to Parent	74,633	51,300	463,126	385,527	220,546
Depreciation, Depletion and Amortization, Nonproduction	1,513	486	2,718	5,786	1,688
Amortization of Debt Discount (Premium)	(42)			(183)
Deferred Income Tax Expense (Benefit)	49,106	(46,078)	(9,645)	98,021	81,395
Share-based Compensation		5,019	3,716	17,106	15,115
Amortization Of Warrant Costs					1,968
Non-Cash Interest Charges on Convertible Debt		5,625			21,554
Other Noncash Income (Expense)	242			1,436	(283)
Change In Equity In Income Of Affiliates	(92,471)	(70,729)	(489,203)	(404,750)	(243,078)
Increase (Decrease) in Income Taxes Receivable					162,036
Increase Decrease In Other Assets	(9,875)	4,085	3,627	1,896	7,941
Increase (Decrease) in Accounts Payable and Accrued Liabilities	(25,832)	737	2,817	(34,507)	59,653
Increase (Decrease) in Accrued Taxes Payable	(8,555)	289	10,767	(75,869)	11,289
Increase or Decrease in Intercompany Taxes Payable	42,214		258,316	258,092
Net Cash Provided by (Used in) Operating Activities	30,933	(49,266)	246,239	252,555	339,824
Payments to Acquire Property, Plant, and Equipment	(2,590)	(1)		(1,924)
Payments for (Proceeds from) Other Investing Activities			45,565
Investment in Affiliates - Net Change	31,756	2,076		7,186	9,308
Net Cash Provided by (Used in) Investing Activities	(29,166)	(2,075)	(45,565)	(5,262)	(9,308)
Proceeds from Issuance of Senior Long-term Debt			1,000,000	500,000
Payments of Debt Issuance Costs			12,237	7,622	1,810
Extinguishment of Debt, Amount	(464,254)		(505)	(75,164)
Proceeds from (Payments for) Other Financing Activities		(313)		(528)	(645)
Increase (Decrease) Due from Affiliates	(460,668)	(62,897)	1,187,647	652,998	336,411
Net Cash Provided by (Used in) Financing Activities	(3,586)	49,286	(200,674)	(236,312)	(338,746)
Cash and Cash Equivalents, Period Increase (Decrease)	(1,819)	(2,055)		10,981	(8,230)
Effect of Exchange Rate on Cash and Cash Equivalents	1,819	2,055		(10,981)	8,230
Proceeds From Issue of Common Stock - Non-Cash		2,138			15,635
Repayments of Long-term Debt					(20,425)
Cash Settlement of Share Based Awards		$ (16,062)