Fair Value Measurements - Quantitative Information (Details)	Sep. 30, 2021	Dec. 31, 2020
IRLCs \| Pull-through rate \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative, measurement input	88	92

Value of input used to measure derivative asset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

Name:	us-gaap_DerivativeAssetMeasurementInput
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant