Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 01, 2017	Apr. 02, 2016
Income Taxes
Income tax benefit	$ 1,970	$ (265)
Effective income tax rate reconciliation
Effective income tax rate (as a percent)	(14.60%)	4.40%
Components of deferred taxes
Gross unrecognized tax benefits	$ 3,600
Gross unrecognized tax benefits which would affect the effective tax rate if recognized	2,200
Amount of estimated decrease in unrecognized tax benefits	$ 1,900

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Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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