v3.25.2
Cover
Jun. 17, 2025
Class of Stock [Line Items]  
Document Type 8-K
Document Period End Date Jun. 17, 2025
Entity Registrant Name First Internet Bancorp
Entity Incorporation, State or Country Code IN
Entity File Number 001-35750
Entity Tax Identification Number 20-3489991
Entity Address, Address Line One 8701 E. 116th Street
Entity Address, City or Town Fishers
Entity Address, State or Province IN
Entity Address, Postal Zip Code 46038
City Area Code 317
Local Phone Number 532-7900
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company false
Entity Central Index Key 0001562463
Amendment Flag false
Common Stock  
Class of Stock [Line Items]  
Title of 12(b) Security Common Stock, without par value
Trading Symbol INBK
Security Exchange Name NASDAQ
6.0% Fixed to Floating Subordinated Notes due 2029  
Class of Stock [Line Items]  
Title of 12(b) Security 6.0% Fixed to Floating Subordinated Notes due 2029
Trading Symbol INBKZ
Security Exchange Name NASDAQ