Contingencies - Narrative (Details) $ in Millions	Sep. 30, 2026 USD ($) loan	Sep. 30, 2025 USD ($) loan
Loss Contingency [Abstract]
Accrued penalty	$ 11.1
Warranty repurchase demands unpaid principal balance	$ 24.8	$ 35.7
Warranty repurchase demands number of loans \| loan	67	100

Amount of loss contingency liability.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-10

Name:	us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant