Fair Value - Schedule of SBA loans held for investment, at fair value, which were valued on a recurring basis and used significant unobservable inputs (Details) - Loans Receivable - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance of SBA loans held for investment at fair value, beginning of period	$ 9,264	$ 10,341
Principal payments	(1,003)	(771)
Charge-offs	(8)	(65)
Repurchase of guaranteed balances previously participated	1,401	0
Total gains during the period	151	49
Balance of SBA loans held for investment at fair value, end of period	$ 9,805	$ 9,554