Mortgage Servicing Rights - Estimated Future Amortization Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Other Intangible Assets
Unpaid principal amount of consumer loans serviced for others	$ 1,400,000		$ 1,400,000		$ 1,400,000
Contractually specified fees, late charges, and ancillary fees	800	$ 900	2,600	$ 2,900
Amortization of mortgage servicing rights	282	$ 333	840	$ 1,587
Details of MSRs
Gross carrying amount	69,406		69,406		69,273
Less: accumulated amortization	63,551		63,551		62,711
Net carrying value	5,855		5,855		$ 6,562
Mortgage servicing assets
Estimated future amortization expenses for MSRs over the next five years
Under one year	852		852
One to two years	757		757
Two to three years	671		671
Three to four years	592		592
Four to five years	$ 523		$ 523