Cover - USD ($)	12 Months Ended
Cover - USD ($)	Jun. 30, 2025	Sep. 04, 2025	Dec. 31, 2024
Cover [Abstract]
Document Type	10-K/A
Amendment Flag	true
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2025
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
Trading Symbol	IROQ
Entity Registrant Name	IF BANCORP, INC.
Entity Central Index Key	0001514743
Current Fiscal Year End Date	--06-30
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		3,351,526
Entity Public Float			$ 56,138,000
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Stock, par value $0.01 per share
Security Exchange Name	NASDAQ
Entity Address, State or Province	IL
Entity Address, Address Line One	201 East Cherry Street
Entity Address, City or Town	Watseka
City Area Code	815
Local Phone Number	432-2476
Entity Tax Identification Number	45-1834449
Entity Incorporation, State or Country Code	MD
Entity File Number	001-35226
Entity Address, Postal Zip Code	60970
Document Financial Statement Error Correction [Flag]	false
ICFR Auditor Attestation Flag	false
Amendment Description	This Amendment No. 1 to the Annual Report on Form 10-K (this “Amendment”) amends the Annual Report on Form 10-K for the fiscal year ended June 30, 2025, originally filed on September 11, 2025 (the “Original Filing”), by IF Bancorp, Inc., a Maryland corporation (“IF Bancorp” or the “Company”). The Company is filing this Amendment to present the information required by Part III of Form 10-K as the Company will not file a definitive annual proxy statement within 120 days of the end of its fiscal year ended June 30, 2025. Pursuant to Rule 12b-15 under the Securities Exchange Act of 1934, as amended, this Amendment also contains new certifications by the principal executive officer and the principal financial officer as required by Section 302 of the Sarbanes-Oxley Act of 2002. Accordingly, Item 15(a)(3) of Part IV is amended to include the currently dated certifications as exhibits. Because no financial statements have been included in this Amendment and this Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the certifications have been omitted. Except as described above or as expressly noted in this Amendment, no other changes have been made to the Original Filing. The Original Filing continues to speak as of and for the periods covered in the Original Filing, and the Company has not updated the disclosures contained therein to reflect any subsequent events.

IF Bancorp, Inc. 10-K/A