Inventories (Inventory reserve rollforward) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 29, 2018	Dec. 30, 2017
Inventory Disclosure [Abstract]
Beginning Balance	$ 9,975	$ 14,202
Additions to reserve during the year	12,169	10,278
Reserves applied and inventories written off during the year	(12,612)	(14,367)
Effect of foreign exchange rate differences	(71)	(138)
Ending Balance	$ 9,461	$ 9,975

Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels.

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