Investments - Available-for-sale (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Basis	$ 475,800	$ 493,746
Gross unrealized gains	215	1,822
Gross unrealized losses	(8,973)	(802)
Carrying value	467,042	494,766
Interest receivable on securities	200	300
Debt securities
Debt Securities, Available-for-sale [Line Items]
Basis	336,551	354,158
Gross unrealized gains	215	1,822
Gross unrealized losses	(8,973)	(802)
Carrying value	327,793	355,178
Beneficial interests in securitization trusts
Debt Securities, Available-for-sale [Line Items]
Basis	139,249	139,588
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Carrying value	$ 139,249	$ 139,588

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, after allowance for credit loss, of accrued interest on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost excluding accrued interest, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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