Note 10 - Accumulated Other Comprehensive Loss - Components of Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Foreign currency translation adjustments, before tax	$ 11,345	$ (5,789)	$ (11,000)
Foreign currency translation adjustments, tax
Foreign currency translation adjustments, net of tax	11,345	(5,789)	(11,000)
Adjustments related to postretirement benefits, before tax	(1,369)	(429)	(24)
Adjustments related to postretirement benefits, tax	121	113	(34)
Adjustments related to postretirement benefits, net of tax	(1,248)	(316)	(58)
Other comprehensive income (loss), before tax	9,974	(6,223)	(11,024)
Other comprehensive income (loss), tax	121	113	(34)
Other comprehensive income (loss), net of tax	10,095	(6,110)	(11,058)
Change in unrealized gain/loss on investments, before tax	(2)	(5)
Change in unrealized gain/loss on investments, tax
Change in unrealized gain/loss on investments, net of tax	$ (2)	$ (5)

Amount, before tax, after reclassification adjustment, of (increase) decrease in accumulated other comprehensive (income) loss for defined benefit plan, attributable to parent entity.

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