| **FAIR VALUE (Fair Value Measurements, Non-recurring) (Details) - USD ($) $ in Thousands**                         | 12 Months Ended |
|--------------------------------------------------------------------------------------------------------------------|-----------------|
||
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Impaired loans held for investment                                                                                 | $ 328,700       | $ 845,900 |   |
| Total carrying value of the loans                                                                                  | 4,542,986       | 2,519,548 |   |
| Goodwill                                                                                                           | 4,444,389       | 8,892,011 |   |
| Impairment of goodwill                                                                                             | 4,447,622       | 0 | $ 0 |
| Nonrecurring                                                                                                       |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Foreclosed assets                                                                                                  | 27,574          | 45,599 |   |
| Vehicle inventory                                                                                                  | 204,120         | 136,136 |   |
| Loans held-for-sale                                                                                                | 2,049,293       |   |   |
| Goodwill                                                                                                           | 1,019,960       |   |   |
| Indefinite lived intangibles                                                                                       | 38,300          |   |   |
| Fair value adjustment                                                                                              | (5,027,888)     | (38,893) | (34,544) |
| Goodwill                                                                                                           | 1,000,000       | 5,500,000 |   |
| Impairment of goodwill                                                                                             | 4,400,000       |   |   |
| Nonrecurring | Impaired loans held for investment                                                                  |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Impaired loans held for investment                                                                                 | 123,118         | 168,917 |   |
| Total carrying value of the loans                                                                                  | 91,300          | 100,200 |   |
| Nonrecurring | Impaired loans held for investment | Provision for credit losses                                    |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Fair value adjustment                                                                                              | (3,618)         | (34,802) | (29,103) |
| Nonrecurring | Foreclosed assets | Miscellaneous income                                                            |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Fair value adjustment                                                                                              | (3,163)         | (4,091) | (5,441) |
| Nonrecurring | Loans held-for-sale | Provision for credit losses                                                   |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Fair value adjustment                                                                                              | (323,514)       | 0 | 0 |
| Nonrecurring | Loans held-for-sale | Miscellaneous income                                                          |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Fair value adjustment                                                                                              | (238,271)       | 0 | 0 |
| Nonrecurring | Goodwill | Impairment of goodwill                                                                   |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Fair value adjustment                                                                                              | (4,447,622)     | 0 | 0 |
| Nonrecurring | Indefinite-lived intangible assets | Amortization of intangibles                                    |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Fair value adjustment                                                                                              | (11,700)        | 0 | $ 0 |
| Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1)                                      |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Foreclosed assets                                                                                                  | 0               | 0 |   |
| Vehicle inventory                                                                                                  | 0               | 0 |   |
| Loans held-for-sale                                                                                                | 0               |   |   |
| Goodwill                                                                                                           | 0               |   |   |
| Indefinite lived intangibles                                                                                       | 0               |   |   |
| Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Impaired loans held for investment |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Impaired loans held for investment                                                                                 | 0               | 0 |   |
| Nonrecurring | Significant Other Observable Inputs (Level 2)                                                       |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Foreclosed assets                                                                                                  | 27,574          | 45,599 |   |
| Vehicle inventory                                                                                                  | 204,120         | 136,136 |   |
| Loans held-for-sale                                                                                                | 0               |   |   |
| Goodwill                                                                                                           | 0               |   |   |
| Indefinite lived intangibles                                                                                       | 0               |   |   |
| Nonrecurring | Significant Other Observable Inputs (Level 2) | Impaired loans held for investment                  |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Impaired loans held for investment                                                                                 | 122,792         | 101,218 |   |
| Nonrecurring | Significant Unobservable Inputs (Level 3)                                                           |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Foreclosed assets                                                                                                  | 0               | 0 |   |
| Vehicle inventory                                                                                                  | 0               | 0 |   |
| Loans held-for-sale                                                                                                | 2,049,293       |   |   |
| Goodwill                                                                                                           | 1,019,960       |   |   |
| Indefinite lived intangibles                                                                                       | 38,300          |   |   |
| Nonrecurring | Significant Unobservable Inputs (Level 3) | Impaired loans held for investment                      |            |   |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                   |            |   |   |
| Impaired loans held for investment                                                                                 | $ 326           | $ 67,699 |   |

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
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Fair value portion of asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
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| - Definition
Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
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