Other income and operating expenses - Components of Other Income and Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Other income
Origination income	$ 12,415	$ 40,836	$ 5,860
Change in repair and denial reserve	(10,168)	(4,133)	345
Other	6,762	4,813	4,873
Total other income	9,009	41,516	11,078
Other operating expenses
Origination costs	24,337	19,815	10,168
Technology expense	7,971	6,722	4,834
Impairment on real estate	2,293	3,520	1,317
Rent and property tax expense	6,680	5,006	4,310
Recruiting, training and travel expenses	1,309	1,419	2,352
Marketing expense	3,025	1,970	2,052
Loan acquisition costs	110	722	575
Financing costs on purchased future receivables	117	1,495	376
Other	12,559	13,700	7,178
Total other operating expenses	$ 58,401	$ 54,369	$ 33,162