Mortgage Servicing Rights - Loans, Fees, Amortization and Carrying Value (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Other Intangible Assets
Unpaid principal amount of consumer loans serviced for others	$ 2,400,000		$ 2,400,000		$ 2,300,000
Contractually specified fees, late charges, and ancillary fees	1,400	$ 1,600	2,900	$ 3,200
Amortization of mortgage servicing rights	1,299	842	3,279	1,606
MSRs
Other Intangible Assets
Amortization of mortgage servicing rights	1,300	$ 800	3,300	$ 1,600
Estimated future amortization expenses for MSRs, next five years
Under one year	2,687		2,687
2021	2,088		2,088
2022	1,625		1,625
2023	1,292		1,292
2024	1,046		1,046
Details of MSRs
Gross carrying amount	65,686		65,686		63,480
Less: accumulated amortization	54,091		54,091		50,812
Net carrying value	$ 11,595		$ 11,595		$ 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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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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