XML 41 R31.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Basis of Presentation (Details) | Sep. 30, 2018 subsidiary
--- | ---
Organization, Consolidation and Presentation of Financial Statements [Abstract] |
Number of wholly-owned subsidiaries | 3

X
- Definition Number Of Wholly Owned Subsidiaries + References No definition available. + Details
Name: | inbk_NumberOfWhollyOwnedSubsidiaries
Namespace Prefix: | inbk_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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