Offsetting assets and liabilities - Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Effect of offsetting recognized liabilities, Derivative
Gross Amounts of Recognized Liabilities	$ 593	$ 212
Effect of offsetting recognized liabilities, Total
Gross Amounts of Recognized Liabilities, Total	2,227,213	2,138,323
Liabilities Presented in the Consolidated Balance Sheets, Total	2,227,213	2,138,323
Financial Instruments, Total	2,225,636	2,136,671
Net Amount, Total	1,577	1,652
FX forwards
Effect of offsetting recognized liabilities, Derivative
Gross Amounts of Recognized Liabilities	593	212
Liabilities Presented in the Consolidated Balance Sheets, Derivative	593	212
Net Amount, Derivative	593	212
Secured borrowings
Effect of offsetting recognized liabilities, Borrowings
Gross Amounts of Recognized Liabilities, Borrowings	2,198,272	2,102,075
Liabilities Presented in the Consolidated Balance Sheets, Borrowings	2,198,272	2,102,075
Financial Instruments, Borrowings	2,198,272	2,102,075
Paycheck Protection Program Liquidity Facility
Effect of offsetting recognized liabilities, Borrowings
Gross Amounts of Recognized Liabilities, Borrowings	28,348	36,036
Liabilities Presented in the Consolidated Balance Sheets, Borrowings	28,348	36,036
Financial Instruments, Borrowings	27,364	34,596
Net Amount, Borrowings	$ 984	$ 1,440