Stock-based Compensation - Summary of Stock Option Activity (Parenthetical) (Detail)	Jun. 30, 2015 $ / shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Closing price per share	$ 16.53

Share based compensation arrangement by share based payment award options closing price per share.

No definition available.

Name:	iroq_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsClosingPricePerShare
Namespace Prefix:	iroq_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant