Loan Servicing Rights - Components of Loan Servicing Rights and Valuation Allowance (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Servicing asset:
Balance at beginning of period	$ 26,288	$ 24,364	$ 25,399	$ 24,512
Additions	4,446	2,097	9,849	4,026
Amortization	(2,885)	(1,717)	(7,399)	(3,794)
Balance before valuation allowance at end of period	27,849	24,744	27,849	24,744
Valuation allowance:
Balance at beginning of period	(2,253)	(32)	(31)	(15)
(Additions)/recoveries	(95)	(89)	(2,317)	(106)
Balance at end of period	(2,348)	(121)	(2,348)	(121)
Loan servicing rights, net	$ 25,501	$ 24,623	$ 25,501	$ 24,623	$ 25,400

Aggregate amount of servicing assets that are subsequently measured at fair value and servicing assets that are subsequently measured using the amortization method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
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-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746

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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122492-111745

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- Definition

Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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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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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Reflects the estimated amount of impairment as of the balance sheet date of recognized servicing assets that are being amortized in proportion to and over the period of estimated net servicing income or loss.

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Amount of increase (decrease) in the valuation allowance for impairment of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer from expenses (recoveries) recognized.

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No definition available.

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