Mortgage banking activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Mortgage servicing rights fair value adjustments	$ 166	$ (10,206)	$ (42,055)
Net (loss) gain on sale of loans, including valuation adjustments on loans held-for-sale	0	(73)	1,234
Total trading account (loss) profit	(784)	(389)	1,033
Total mortgage banking activities	42,450	50,133	10,401
Mortgage banking activities
Mortgage servicing fees	36,487	38,105	43,234
Mortgage servicing rights fair value adjustments	236	(10,206)	(42,055)
Total mortgage servicing fees, net of fair value adjustments	36,723	27,899	1,179
Net (loss) gain on sale of loans, including valuation adjustments on loans held-for-sale	(251)	21,684	31,215
Realized gains (losses) on closed derivative positions	6,635	1,323	(10,586)
Total trading account (loss) profit	6,635	1,323	(10,586)
Losses on repurchased loans, including interest advances	(657)	(773)	(11,407)
Total mortgage banking activities	$ 42,450	$ 50,133	$ 10,401