| **GOODWILL AND OTHER INTANGIBLES (Finite-lived and Indefinite-lived Intangibles) (Details) - USD ($) $ in Thousands** | 9 Months Ended |            |
|-----------------------------------------------------------------------------------------------------------------------|----------------|------------|
||
| **Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]**                                      |           |       |
| Intangibles subject to amortization                                                                                   | $ 614,419      | $ 649,276  |
| Accumulated Amortization                                                                                              | (536,185)      | (483,325)  |
| Net Carrying Amount                                                                                                   | 614,419        | 667,276    |
| Trade name                                                                                                            |           |       |
| **Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]**                                      |           |       |
| Intangibles not subject to amortization                                                                               |           | 18,000     |
| Dealer networks                                                                                                       |           |       |
| **Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]**                                      |           |       |
| Intangibles subject to amortization                                                                                   | 475,429        | 504,839    |
| Accumulated Amortization                                                                                              | (104,571)      | (75,161)   |
| Chrysler relationship                                                                                                 |           |       |
| **Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]**                                      |           |       |
| Intangibles subject to amortization                                                                                   | 98,750         | 110,000    |
| Accumulated Amortization                                                                                              | (40,000)       | (28,750)   |
| Core deposit intangibles                                                                                              |           |       |
| **Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]**                                      |           |       |
| Intangibles subject to amortization                                                                                   | 0              | 763        |
| Accumulated Amortization                                                                                              | $ (295,842)    | (295,079)  |
| Intangible asset useful life                                                                                          | 10 years       |       |
| Trade name                                                                                                            |           |       |
| **Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]**                                      |           |       |
| Intangibles subject to amortization                                                                                   | $ 17,400       |       |
| Accumulated Amortization                                                                                              | (600)          |       |
| Other intangibles                                                                                                     |           |       |
| **Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]**                                      |           |       |
| Intangibles subject to amortization                                                                                   | 22,840         | 33,674     |
| Accumulated Amortization                                                                                              | $ (95,171)     | $ (84,335) |
| Intangible Assets, Amortization Period | Trade name                                                                   |           |       |
| **Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]**                                      |           |       |
| Intangible asset useful life                                                                                          | 15 years       |       |

| X                                                                                                                                                                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
[Line Items] for Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Table]
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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
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| - Definition
Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.
+ References
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| - Definition
Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.
+ References
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| - Definition
Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.
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