Servicing Rights - Key Assumptions and the Sensitivity of the Fair Value (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022	Jun. 30, 2023	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Servicing Assets at Fair Value [Line Items]
Balance of mortgage loans serviced for others	$ 982,098,000	$ 898,840,000
Weighted average rate of note (percent)	3.82%	3.47%
MSR as a percentage of serviced loans	1.97%	2.07%
Mortgage servicing rights
Servicing Assets at Fair Value [Line Items]
Fair value of MSRs	$ 19,396,000	$ 18,635,000	$ 18,248,000	$ 17,709,000	$ 16,301,000	$ 13,724,000
Expected weighted-average life (in years)	10 years 9 months 25 days	9 years 5 months 15 days
Key assumptions:
Constant prepayment rate (percent)	7.88%	6.64%
Constant prepayment rate, impact on fair value from 10% adverse change	$ (536,000)	$ (518,000)
Constant prepayment rate, impact on fair value from 25% adverse change	$ (984,000)	$ (1,233,000)
Discount rate (percent)	10.97%	11.25%
Discount rate, impact on fair value from 100 basis point increase	$ (821,000)	$ (635,000)
Discount rate, impact on fair value from 200 basis point increase	(1,579,000)	(1,224,000)
Cost to service assumptions ($ per loan)	82	91
Cost to service assumptions, impact on fair value from 10% adverse change	(156,000)	(153,000)
Cost to service assumptions, impact on fair value from 25% adverse change	$ (389,000)	$ (382,000)