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, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gains (Losses) included in earnings	$ (6,225)	$ 2,255	$ (7,611)	$ 3,258
Changes in unrealized gains (losses) included in earnings relating to assets still held	(2,723)	5,319	(1,430)	9,577
Mortgage banking activities
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gains (Losses) included in earnings	(6,217)	2,258	(7,593)	3,275
Changes in unrealized gains (losses) included in earnings relating to assets still held	(2,732)	5,318	(1,447)	9,571
Trading account (loss) profit
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gains (Losses) included in earnings	(8)	(3)	(18)	(17)
Changes in unrealized gains (losses) included in earnings relating to assets still held	$ 9	$ 1	$ 17	$ 6