Loan Servicing - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Payments for (Proceeds from) Mortgage Servicing Rights [Abstract]
Unpaid principal balances of loans serviced for others totaled	$ 1,500,000		$ 1,500,000
Aggregate fair value of capitalized mortgage servicing rights	14,900		12,500
Mortgage servicing rights, net	14,863		12,472
Reductions	2,142		653
Mortgage servicing rights, net impairment	$ 2,142	$ (4,673)	$ (4,500)

The adjustment to the carrying value of the rights retained or purchased to service mortgages. These adjustments are made when the estimate of the fair value is changed. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (a)(6)
-URI http://asc.fasb.org/extlink&oid=125521744&loc=d3e122739-111746

Name:	us-gaap_MortgageServicingRightsMSRImpairmentRecovery
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration