Note 8 - Long-Term Debt (Details) - Amortized Financing Costs (USD $) In Thousands, unless otherwise specified	12 Months Ended
Sep. 27, 2014
Amortized Financing Costs [Abstract]
2015	$ 102
2016	$ 69

The amount of amortization costs in the next 12 months.

No definition available.

Name:	iiin_AmortizationOfFinancingCostsNext12Months
Namespace Prefix:	iiin_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration