Other income and operating expenses - Components of Other Income and Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Other income
Origination income	$ 33,617	$ 1,709	$ 36,112	$ 2,517
Release of repair and denial reserve	(2,651)	(76)	(2,515)	(165)
Other	628	1,159	2,070	1,340
Total other income	31,594	2,792	35,667	3,692
Other operating expenses
Origination costs	9,430	2,734	12,455	3,923
Technology expense	1,742	1,057	3,322	2,158
Impairment on real estate	106	375	3,075	680
Rent and property tax expense	1,200	1,103	2,384	1,794
Recruiting, training and travel expenses	235	592	859	1,179
Marketing expense	385	582	931	1,127
Loan acquisition costs	356	(5)	453	105
Financing costs on purchased future receivables	789		1,413
Other	3,502	1,647	6,595	3,981
Total other operating expenses	$ 17,745	$ 8,085	$ 31,487	$ 14,947