Earnings (Loss) Per Share (EPS) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Net Income (Loss) Available to Common Stockholders, Diluted [Abstract]
Net income (loss)	$ 2,990	$ (770)	$ (1,349)	$ (13,430)
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Basic (in shares)	31,302,000	30,767,000	31,159,000	30,743,000
Stock options, restricted stock and restricted stock units (in shares)	680,000	0	0	0
Denominator for diluted EPS (in shares)	31,982,000	30,767,000	31,159,000	30,743,000
Basic EPS (in dollars per share)	$ 0.10	$ (0.03)	$ (0.04)	$ (0.44)
Diluted EPS (in dollars per share)	$ 0.09	$ (0.03)	$ (0.04)	$ (0.44)
Anitdilutive Securities Excluded From Earnings Per Share [Abstract]
Time-vested stock options, restricted stock and restricted stock units (in shares)	556,000	1,916,000	1,599,000	1,916,000
Performance-vested stock options and restricted stock units (in shares)	180,000	417,000	451,000	417,000