Mortgage Servicing Rights - Loans, Fees, Amortization and Carrying Value (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Other Intangible Assets
Unpaid principal amount of consumer loans serviced for others	$ 1,900,000		$ 1,900,000		$ 2,200,000
Contractually specified fees, late charges, and ancillary fees	1,200	$ 1,400	2,500	$ 2,900
Amortization of mortgage servicing rights	1,283	$ 1,299	1,829	$ 3,279
Details of MSRs
Gross carrying amount	68,961		68,961		67,856
Less: accumulated amortization	58,954		58,954		57,125
Net carrying value	10,007		10,007		$ 10,731
MSRs
Estimated future amortization expenses for MSRs over the next five years
Under one year	1,921		1,921
One to two years	1,516		1,516
Two to three years	1,230		1,230
Three to four years	1,014		1,014
Four to five years	$ 847		$ 847