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
	Mar. 31, 2023	Mar. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gain (loss) included in earnings	$ (1,385)	$ 1,003
Changes in unrealized gains (losses) included in earnings relating to assets still held	1,295	4,256
Mortgage banking activities
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gain (loss) included in earnings	(1,376)	1,017
Changes in unrealized gains (losses) included in earnings relating to assets still held	1,286	4,252
Trading account (loss) profit
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Abstract
Gain (loss) included in earnings	(9)	(14)
Changes in unrealized gains (losses) included in earnings relating to assets still held	$ 9	$ 4