| **OTHER ASSETS - Narrative (Details) $ in Thousands** | 12 Months Ended |
|-------------------------------------------------------|-----------------|
||
| **Lessee, Lease, Description [Line Items]**           |            |   |   |
| Number of options to renew | option                   | 1               |   |   |
| Operating lease expense                               | $ 154,500       | $ 153,800 | $ 140,800 |
| Sublease income                                       | 4,000           | 4,000 | 4,400 |
| Operating lease rental payments                       | 152,292         | 146,133 |   |
| Santander | Office Space                              |            |   |   |
| **Lessee, Lease, Description [Line Items]**           |            |   |   |
| Operating lease rental payments                       | $ 0             | $ 5,800 | $ 5,900 |
| Minimum                                               |            |   |   |
| **Lessee, Lease, Description [Line Items]**           |            |   |   |
| Renewal term (in years)                               | 1 year          |   |   |
| Maximum                                               |            |   |   |
| **Lessee, Lease, Description [Line Items]**           |            |   |   |
| Renewal term (in years)                               | 5 years         |   |   |

| X                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Lessee, Operating Leases, Number of Options to Renew
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of operating lease expense. Excludes sublease income.
+ References
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of sublease income excluding finance and operating lease expense.
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