Mortgage Servicing Rights - Estimated Future Amortization Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Other Intangible Assets
Unpaid principal amount of consumer loans serviced for others	$ 1,600,000		$ 1,700,000
Contractually specified fees, late charges, and ancillary fees	1,000	$ 1,300
Amortization of mortgage servicing rights	736	$ 545
Details of MSRs
Gross carrying amount	69,187		69,103
Less: accumulated amortization	61,537		60,801
Net carrying value	7,650		$ 8,302
Mortgage servicing assets
Estimated future amortization expenses for MSRs over the next five years
Under one year	1,296
One to two years	1,094
Two to three years	928
Three to four years	787
Four to five years	$ 672

Principal amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of contractually specified servicing fee, late fee, and ancillary fee recognized as income for servicing asset and servicing liability.

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-Publisher FASB
-Name Accounting Standards Codification
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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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