Mortgage Servicing Rights - Loans, Fees, Amortization and Carrying Value (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Other Intangible Assets
Unpaid principal amount of consumer loans serviced for others	$ 2,000,000		$ 2,200,000
Contractually specified fees, late charges, and ancillary fees	1,300	$ 1,500
Amortization of mortgage servicing rights	545	$ 1,980
Details of MSRs
Gross carrying amount	68,540		67,856
Less: accumulated amortization	57,671		57,125
Net carrying value	10,869		$ 10,731
MSRs
Estimated future amortization expenses for MSRs, next five years
Under one year	2,013
One to two years	1,615
Two to three years	1,323
Three to four years	1,100
Four to five years	$ 924