XML 59 R45.htm IDEA: XBRL DOCUMENT
v3.25.3

Organization and Basis of Presentation (Details) shares in Millions | Oct. 17, 2025 shares | Sep. 30, 2025 location state
--- | --- | ---
Product Information [Line Items] |  |
Number of locations | location |  | 340
Number of states in which offices are located | state |  | 9
Subsequent Event |  |
Product Information [Line Items] |  |
Additional shares authorized (in shares) | shares | 250.0 |

X
- Definition Number Of Locations + References No definition available. + Details
Name: | fbc_NumberOfLocations
Namespace Prefix: | fbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number Of States In Which Offices Are Located + References No definition available. + Details
Name: | fbc_NumberOfStatesInWhichOfficesAreLocated
Namespace Prefix: | fbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_ProductInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of additional shares authorized for issuance under share-based payment arrangement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-4 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |