Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Sep. 29, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	(14.20%)	(31.40%)
Income (loss) before provision for income taxes	$ 11,990	$ 8,717	$ 11,911	$ (3,358)
Benefit for income taxes	1,700	$ 2,741	430	$ 1,386
Unrecognized Tax Benefits	11,500		11,500
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	1,200		1,200
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 10,800		$ 10,800