Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2016	Jun. 28, 2015	Jul. 03, 2016	Jun. 28, 2015
Earnings Per Share Reconciliation
Basic EPS - net income	$ 24,940	$ 37,332	$ 47,842	$ 65,344
Basic EPS - shares	40,922	41,629	40,890	41,711
Basic EPS - per share amount	$ 0.61	$ 0.90	$ 1.17	$ 1.57
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	467	415	414	431
Dilutive effect of stock options, restricted stock units, and shares issuable to Philips - per share amount	$ (0.01)	$ (0.01)	$ (0.01)	$ (0.02)
Diluted EPS - net income	$ 24,940	$ 37,332	$ 47,842	$ 65,344
Diluted EPS - shares	41,389	42,044	41,304	42,142
Diluted EPS - per share amount	$ 0.60	$ 0.89	$ 1.16	$ 1.55