Note 14 - Business Segment Information (Details) - Net Sales By Product Line (USD $) In Thousands, unless otherwise specified	12 Months Ended
Sep. 27, 2014	Sep. 28, 2013	Sep. 29, 2012
Net sales:
Revenue	$ 408,978	$ 363,896	$ 363,303
Welded Wire Reinforcement [Member]
Net sales:
Revenue	255,294	227,957	230,049
PC Strand [Member]
Net sales:
Revenue	$ 153,684	$ 135,939	$ 133,254

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration