Schedule II - Valuation and Qualifying Accounts and Reserves - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016	Jan. 04, 2016	Dec. 28, 2014
Allowance for Doubtful Accounts [Member]
BALANCE, AT BEGINNING OF YEAR		$ 3,493	$ 3,780	$ 4,479		$ 5,896
CHARGED TO COSTS AND EXPENSES	[1]	635	(243)	212
CHARGED TO OTHER ACCOUNTS		0	0	0
DEDUCTIONS	[2]	922	456	1,629
Business Restructuring Reserves [Member]
BALANCE, AT BEGINNING OF YEAR		2,568	10,291	104		7,179
CHARGED TO COSTS AND EXPENSES	[1]	3,999	11,769	(481)
CHARGED TO OTHER ACCOUNTS	[3]	3,300	8,019	0
DEDUCTIONS	[4]	3,724	1,582	6,594
Warranty Reserves [Member]
BALANCE, AT BEGINNING OF YEAR		4,111	5,529	4,759	$ 4,759	$ 3,954
CHARGED TO COSTS AND EXPENSES	[1]	2,071	3,149	2,584
CHARGED TO OTHER ACCOUNTS		0	0	0
DEDUCTIONS	[5]	$ 3,489	$ 2,379	$ 1,779

[1] Includes changes in foreign currency exchange rates.

[2] Write off of bad debt, and recovering of previously provided for amounts.

[3] Direct reduction of asset carrying value, not included in restructuring reserve.

[4] Cash payments.

[5] Represents credits and costs applied against reserve and adjustments to reflect actual exposure.