Reinsurance and Indemnification - Additional Information (Details) - National Flood Insurance Program $ in Billions	Sep. 30, 2025 USD ($)
Reinsurance
Borrowing capacity is reduced	$ 1.0
Exceeded by the current program debt	$ 22.5

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_EffectsOfReinsuranceLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration