Stock-based Compensation- Summary of ESOP Shares (Parenthetical) (Detail) - $ / shares	12 Months Ended
Jun. 30, 2016	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
ESOP, closing price per share	$ 18.34	$ 16.53

Closing price of share to calculate unearned ESOP shares.

No definition available.

Name:	iroq_ClosingPriceOfShareToCalculateUnearnedEsopShares
Namespace Prefix:	iroq_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration