Fair Value Of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes, Loans and Financing Receivable, Net	$ 11,502,472	$ 10,998,274
Restricted Cash and Investments	778,213	728,908
Restricted Cash and Cash Equivalents	53,101	14,808
Restricted Cash - Derivative Collateral	3,900	4,200
Interest Rate Swap Agreements - Assets		133
Interest Rate Cap Agreements Purchased	784	386
Investment Foreign Currency, Contract, Amount Purchased	2,221
Senior Notes	1,500,000	1,500,000
Interest Rate Swap Agreements - Liabilities		133
Interest Rate Cap Agreements - Sold	795	394
Investment Foreign Currency, Contract, Amount Sold	2,257
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	2,896,870	1,289,494
Notes, Loans and Financing Receivable, Net	11,502,472	10,998,274
Restricted Cash and Investments	778,213	728,908
Restricted Cash and Cash Equivalents	53,101	14,808
Restricted Cash - Derivative Collateral	19,522	24,774
Interest Rate Swap Agreements - Assets		133
Interest Rate Cap Agreements Purchased	784	386
Investment Foreign Currency, Contract, Amount Purchased	2,221
Syndicated And Lease Warehouse Facilities	2,719,134	354,203
Securitization Notes Payable - Public Transactions	8,600,162	8,533,321
Securitization Notes Payable - Private Transactions	429,532	489,987
Senior Notes	1,500,000	1,500,000
Interest Rate Swap Agreements - Liabilities		133
Interest Rate Cap Agreements - Sold	795	394
Investment Foreign Currency, Contract, Amount Sold	2,257
Portion at Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	2,896,870	1,289,494
Notes, Loans and Financing Receivable, Net	11,799,364	11,313,481
Restricted Cash and Investments	778,213	728,908
Restricted Cash and Cash Equivalents	53,101	14,808
Restricted Cash - Derivative Collateral	19,522	24,774
Interest Rate Swap Agreements - Assets		133
Interest Rate Cap Agreements Purchased	784	386
Investment Foreign Currency, Contract, Amount Purchased	2,221
Syndicated And Lease Warehouse Facilities		354,203
Securitization Notes Payable - Public Transactions	8,742,701	8,669,106
Securitization Notes Payable - Private Transactions	442,003	502,332
Senior Notes	1,606,250	1,620,000
Interest Rate Swap Agreements - Liabilities		133
Interest Rate Cap Agreements - Sold	795	394
Investment Foreign Currency, Contract, Amount Sold	2,257
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Cap Agreements Purchased	784	386
Investment Foreign Currency, Contract, Amount Purchased	2,221
Interest Rate Cap Agreements - Sold	795	394
Investment Foreign Currency, Contract, Amount Sold	2,257
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Swap Agreements - Assets		133
Interest Rate Swap Agreements - Liabilities		$ 133

Value as of the balance sheet date of interest rate cap assets.

No definition available.

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- Definition

Value of interest rate cap liabilities at the balance sheet date.

+ References

No definition available.

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- Definition

Value as of the balance sheet date of interest rate swap assets.

+ References

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Value for interest rate swap liabilities at the balance sheeet date.

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- Definition

Restricted Cash - Derivative Collateral

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- Definition

Securitization Notes Payable - Private Transactions

+ References

No definition available.

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- Definition

Securitization Notes Payable - Public Transactions

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- Definition

Syndicated And Lease Warehouse Facilities

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No definition available.

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- Definition

The amount of a currency that the reporting entity is obligated to purchase at settlement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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The amount of a currency that the reporting entity is obligated to sell at settlement.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 8

-Footnote 2

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Paragraph 7, 8, 9, 10

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

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-Name Accounting Standards Codification

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-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 7

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- Definition

Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

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-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Article 5

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- Definition

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

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-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-BRD

-Paragraph 80

-Subparagraph Exhibit 4-8, 3

-IssueDate 2006-05-01

-Chapter 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

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Cash and investments whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements. For use in an unclassified balance sheet.

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

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-Section 03

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-Subparagraph (SX 210.7-03.16(a))

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