Note 4 - Other Investments (Details Textual) € in Millions, $ in Millions	9 Months Ended
Sep. 26, 2015 USD ($)	Sep. 26, 2015 EUR (€)	Sep. 26, 2015 USD ($)	Dec. 27, 2014 EUR (€)	Dec. 27, 2014 USD ($)
Marketable Securities, Equity Securities		€ 10.0	$ 11.2	€ 9.9	$ 12.1
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	$ 0.1

Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 10A

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580

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