Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information or footnotes necessary for a complete presentation of financial condition, results of operations, changes in shareholders’ equity, or cash flows in accordance with GAAP. In our opinion, all adjustments (consisting only of normal recurring adjustments) necessary for a fair presentation have been included. The results of operations for the three and nine months ended September 30, 2021 are not necessarily indicative of the results expected for the year ending December 31, 2021 or any other period. The September 30, 2021 condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the First Internet Bancorp Annual Report on Form 10-K for the year ended December 31, 2020. The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make estimates, judgments, or assumptions that could have a material effect on the carrying value of certain assets and liabilities. These estimates, judgments, and assumptions affect the amounts reported in the condensed consolidated financial statements and the disclosures provided. The determination of the allowance for loan losses, valuations and impairments of investment securities, valuation of the servicing asset and the accounting for income tax expense are highly dependent upon management’s estimates, judgments, and assumptions, and changes in any of these could have a significant impact on the condensed consolidated financial statements. The condensed consolidated financial statements include the accounts of First Internet Bancorp (the “Company”), its wholly owned subsidiary, First Internet Bank of Indiana (the “Bank”), and the Bank’s three wholly owned subsidiaries, First Internet Public Finance Corp., JKH Realty Services, LLC and SPF15, Inc. All significant intercompany accounts and transactions have been eliminated in consolidation. The Company is subject to claims and lawsuits that arise primarily in the ordinary course of business. It is the opinion of management that the disposition or ultimate resolution of such claims and lawsuits will not have a material adverse effect on the consolidated financial position, results of operations, and cash flows of the Company. Certain reclassifications have been made to the 2020 financial statements to conform to the presentation of the 2021 financial statements. These reclassifications had no effect on net income. Revision of Previously Issued Financial Statements The Company has revised amounts reported in previously issued notes to financial statements for the periods presented in this Quarterly Report on Form 10-Q due to immaterial clerical errors. The clerical errors caused the fair value associated with interest rate swap liabilities to be understated in the notes to financial statements for the period ended December 31, 2020 and had no impact on the consolidated balance sheet, income statement or statement of cash flows. The Company evaluated the impact of the clerical errors to our previously issued financial statements in accordance with SEC Staff Accounting Bulletins No. 99 and No. 108 and, based upon quantitative and qualitative factors, determined that the clerical errors were not material to the previously issued financial statements and disclosures included in our Annual Report on Form 10-K for the year ended December 31, 2020.