Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2015	Sep. 28, 2014	Sep. 27, 2015	Sep. 28, 2014
Earnings Per Share Reconciliation
Basic EPS - net income	$ 10,418	$ 21,647	$ 75,762	$ 71,671
Basic EPS - shares	41,404	41,891	41,624	42,053
Basic EPS - per share amount	$ 0.25	$ 0.52	$ 1.82	$ 1.70
Dilutive effect of stock options, restricted stock units, and shares issuable to Philips - net income	$ 0	$ 0	$ 0	$ 0
Dilutive effect of stock options, restricted stock units, and shares issuable to Philips - shares	416	574	426	571
Dilutive effect of stock options, restricted stock units, and shares issuable to Philips - per share amount	$ 0.00	$ (0.01)	$ (0.02)	$ (0.02)
Diluted EPS - net income	$ 10,418	$ 21,647	$ 75,762	$ 71,671
Diluted EPS - shares	41,820	42,465	42,050	42,624
Diluted EPS - per share amount	$ 0.25	$ 0.51	$ 1.80	$ 1.68