Mortgage Servicing Rights - Summary of Activity in Mortgage Servicing Rights (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Fair value at beginning of period	$ 1,806	$ 2,404
Mortgage servicing rights beginning balance	1,806	2,172
Additions	203	99
Amortization	(231)	(118)
Adjustments to valuation allowance	369	(217)
Mortgage servicing rights ending balance	2,147	1,936
Fair value at end of period	$ 2,153	$ 1,958

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122492-111745

Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

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Period Type:	instant

- 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.

+ References

+ Details

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- Definition

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

+ References

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- Definition

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

+ References

No definition available.

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- Definition

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

+ References

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- Definition

Amount of increase (decrease) in the amortized amount from a decrease (increase) in the valuation allowance applied to the servicing asset for a contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

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