Mortgage Servicing Rights - Loans, Fees, Amortization and Carrying Value (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Other Intangible Assets
Unpaid principal amount of consumer loans serviced for others	$ 2,300,000		$ 2,300,000		$ 2,300,000
Contractually specified fees, late charges, and ancillary fees	1,400	$ 1,600	4,400	$ 4,800
Amortization of mortgage servicing rights	1,402	978	4,681	2,584
MSRs
Other Intangible Assets
Amortization of mortgage servicing rights	1,400	$ 1,000	4,700	$ 2,600
Estimated future amortization expenses for MSRs, next five years
Under one year	2,587		2,587
2021	1,985		1,985
2022	1,550		1,550
2023	1,233		1,233
2024	994		994
Details of MSRs
Gross carrying amount	66,415		66,415		63,480
Less: accumulated amortization	55,493		55,493		50,812
Net carrying value	$ 10,922		$ 10,922		$ 12,668

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.

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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
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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 before 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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