Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	27.40%	212.10%
Income (loss) before provision for income taxes	$ 4,116	$ 687	$ (79)	$ (12,075)
Provision for income taxes	1,126	$ 1,457	1,270	$ 1,355
Unrecognized Tax Benefits	11,200		11,200
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	600		600
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 10,400		$ 10,400