Mortgage banking activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Mortgage servicing rights fair value adjustments	$ (11,370)	$ (12,339)	$ 166
Net gain (loss) on sale of loans, including valuation on loans held for sale	440	(115)	0
Total trading account profit	1,445	1,382	(784)
Total mortgage banking activities	19,059	21,497	42,450
Mortgage banking activities
Mortgage servicing fees	30,227	32,981	36,487
Mortgage servicing rights fair value adjustments	(11,370)	(11,589)	236
Total mortgage servicing fees, net of fair value adjustments	18,857	21,392	36,723
Net gain (loss) on sale of loans, including valuation on loans held for sale	317	(88)	(251)
Unrealized gains (loss) on outstanding derivative positions	185	(138)	0
Realized (loss) gains on closed derivative positions	(150)	614	6,635
Total trading account profit	35	476	6,635
Losses on repurchased loans, including interest advances	(150)	(283)	(657)
Total mortgage banking activities	$ 19,059	$ 21,497	$ 42,450