Variable interest entities and securitization activities - Consolidated VIE Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Assets
Cash and cash equivalents	$ 226,286		$ 197,651
Restricted cash	29,971		$ 29,179
Other assets	379,413	$ 300,175
Total Assets	11,774,333	12,441,217
Liabilities
Secured borrowings	2,311,969	2,102,075
Accounts payable and other accrued liabilities	204,766	207,481
Total Liabilities	9,374,107	9,794,455
Consolidated VIEs
Assets
Loans, net	6,001,409	6,611,325
Loans, held for sale	9,725
Liabilities
Secured borrowings	4,407,241	5,068,453
Reportable Legal Entities | Consolidated VIEs
Assets
Cash and cash equivalents	4	671
Restricted cash	22,778	93,240
Loans, net	6,001,409	6,611,325
Loans, held for sale	9,725
Preferred equity investments	108,423	108,423
Other assets	108,231	83,486
Total Assets	6,250,570	6,897,145
Liabilities
Secured borrowings	4,407,241	5,068,453
Due to third parties	2,773	2,944
Accounts payable and other accrued liabilities	1	34
Total Liabilities	$ 4,410,015	$ 5,071,431