| Schedule of Segment Reporting Information, by Segment [Table Text Block] |
| Three Months Ended March 31, 2025 | | CaaS | | | Auto Finance | | | Total | |
| Revenue and other income: | | | | | | | | | | | | |
| Consumer loans, including past due fees | | $ | 238,503 | | | $ | 9,152 | | | $ | 247,655 | |
| Fees and related income on earning assets | | | 78,323 | | | | 18 | | | | 78,341 | |
| Other revenue | | | 18,698 | | | | 179 | | | | 18,877 | |
| Total operating revenue and other income | | | 335,524 | | | | 9,349 | | | | 344,873 | |
| Other non-operating income | | | 7 | | | | 286 | | | | 293 | |
| Total revenue and other income | | | 335,531 | | | | 9,635 | | | | 345,166 | |
| Interest expense | | | (46,984 | ) | | | (546 | ) | | | (47,530 | ) |
| Provision for credit losses | | | (25 | ) | | | (1,043 | ) | | | (1,068 | ) |
| Changes in fair value of loans | | | (178,345 | ) | | | — | | | | (178,345 | ) |
| Net margin | | | 110,177 | | | | 8,046 | | | | 118,223 | |
| Operating expenses: | | | | | | | | | | | | |
| Salaries and benefits | | | (14,286 | ) | | | (1,217 | ) | | | (15,503 | ) |
| Card and loan servicing | | | (28,857 | ) | | | (3,295 | ) | | | (32,152 | ) |
| Marketing and solicitation | | | (20,327 | ) | | | (7 | ) | | | (20,334 | ) |
| Depreciation | | | (778 | ) | | | (19 | ) | | | (797 | ) |
| Other | | | (7,534 | ) | | | (1,035 | ) | | | (8,569 | ) |
| Total operating expenses | | | (71,782 | ) | | | (5,573 | ) | | | (77,355 | ) |
| Income before income taxes | | $ | 38,395 | | | $ | 2,473 | | | $ | 40,868 | |
| Total assets | | $ | 3,185,715 | | | $ | 86,450 | | | $ | 3,272,165 | |
| Three Months Ended March 31, 2024 | | CaaS | | | Auto Finance | | | Total | |
| Revenue and other income: | | | | | | | | | | | | |
| Consumer loans, including past due fees | | $ | 220,039 | | | $ | 10,335 | | | $ | 230,374 | |
| Fees and related income on earning assets | | | 47,885 | | | | 20 | | | | 47,905 | |
| Other revenue | | | 11,677 | | | | 218 | | | | 11,895 | |
| Total operating revenue and other income | | | 279,601 | | | | 10,573 | | | | 290,174 | |
| Other non-operating income | | | 282 | | | | 250 | | | | 532 | |
| Total revenue and other income | | | 279,883 | | | | 10,823 | | | | 290,706 | |
| Interest expense | | | (34,236 | ) | | | (827 | ) | | | (35,063 | ) |
| Provision for credit losses | | | — | | | | (2,944 | ) | | | (2,944 | ) |
| Changes in fair value of loans | | | (159,171 | ) | | | — | | | | (159,171 | ) |
| Net margin | | | 86,476 | | | | 7,052 | | | | 93,528 | |
| Operating expenses: | | | | | | | | | | | | |
| Salaries and benefits | | | (11,891 | ) | | | (1,421 | ) | | | (13,312 | ) |
| Card and loan servicing | | | (23,458 | ) | | | (3,364 | ) | | | (26,822 | ) |
| Marketing and solicitation | | | (10,396 | ) | | | (32 | ) | | | (10,428 | ) |
| Depreciation | | | (636 | ) | | | (18 | ) | | | (654 | ) |
| Other | | | (8,281 | ) | | | (1,210 | ) | | | (9,491 | ) |
| Total operating expenses | | | (54,662 | ) | | | (6,045 | ) | | | (60,707 | ) |
| Income before income taxes | | $ | 31,814 | | | $ | 1,007 | | | $ | 32,821 | |
| Total assets | | $ | 2,682,189 | | | $ | 105,026 | | | $ | 2,787,215 | |
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