Goodwill and other intangible assets - Components of other intangible assets subject to amortization (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 27,096	$ 27,096
Accumulated Amortization	17,297	14,912
Net Carrying Value	9,799	12,184
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	12,810	12,810
Accumulated Amortization	10,995	10,034
Net Carrying Value	1,815	2,776
Other customer relationship
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	14,286	14,286
Accumulated Amortization	6,302	4,878
Net Carrying Value	$ 7,984	$ 9,408