Fair value measurement - Gains and losses (realized and unrealized) included in earnings for level 3 assets and liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gains (Losses) included in earnings	$ (1,953)	$ (6,225)	$ (5,893)	$ (7,611)
Changes in unrealized gains (losses) included in earnings relating to assets still held	510	(2,723)	(1,190)	(1,430)
Mortgage banking activities
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gains (Losses) included in earnings	(1,945)	(6,217)	(5,384)	(7,593)
Changes in unrealized gains (losses) included in earnings relating to assets still held	500	(2,732)	(702)	(1,447)
Trading account profit (loss)
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gains (Losses) included in earnings	(8)	(8)	(9)	(18)
Changes in unrealized gains (losses) included in earnings relating to assets still held	10	$ 9	12	$ 17
Provision for credit losses
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gains (Losses) included in earnings	0		(500)
Changes in unrealized gains (losses) included in earnings relating to assets still held	$ 0		$ (500)