Schedule II - Valuation and Qualifying Accounts - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017		Dec. 31, 2016		Dec. 26, 2015
Allowance for Doubtful Accounts [Member]
us-gaap_ValuationAllowanceAbstract
Balance, beginning of year	$ 81		$ 71		$ 179
Additions (reductions) not charged to expense	204	[1]	(4)	[2]	1	[2]
Additions (reduction) charged (credited) to expense	6		13		19
Deductions/write-offs	61		(1)		128
Balance, end of year	230		81		71
Inventory Valuation Reserve [Member]
us-gaap_ValuationAllowanceAbstract
Balance, beginning of year	21,485		26,653		27,851
Additions (reductions) not charged to expense	2,661	[1]	1,789	[3]	(648)	[2]
Additions (reduction) charged (credited) to expense	1,148		1,125		2,409
Deductions/write-offs	4,106		8,082		2,959
Balance, end of year	$ 21,188		$ 21,485		$ 26,653

[1] Changes in reserve balances resulting from foreign currency impact, reclassifications and acquisition of Kita.

[2] Changes in reserve balances resulting from foreign currency impact.

[3] Changes in reserve balances resulting from foreign currency impact and reclassifications from other reserves.