Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014
Earnings Per Share Reconciliation
Basic EPS - net income	$ 37,332	$ 24,948	$ 65,344	$ 50,026
Basic EPS - shares	41,629	42,080	41,711	42,135
Basic EPS - per share amount	$ 0.90	$ 0.59	$ 1.57	$ 1.19
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	415	547	431	566
Dilutive effect of stock options, restricted stock units, and shares issuable to Philips - per share amount	$ (0.01)	$ 0.00	$ (0.02)	$ (0.02)
Diluted EPS - net income	$ 37,332	$ 24,948	$ 65,344	$ 50,026
Diluted EPS - shares	42,044	42,627	42,142	42,701
Diluted EPS - per share amount	$ 0.89	$ 0.59	$ 1.55	$ 1.17