Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Earnings Per Share Reconciliation
Basic EPS	$ 25,078	$ 26,801
Basic EPS - shares	42,191	38,522
Basic EPS - per share amount	$ 0.59	$ 0.70
Dilutive effect of 2.875% convertible debt - net income	0	455
Dilutive effect of 2.875% convertible debt - shares	0	3,033
Dilutive effect of 2.875% convertible debt - per share amount	$ 0.00	$ (0.04)
Dilutive effect of stock options, restricted stock units, and shares issuable to Philips - net income	0	0
Dilutive effect of stock options, restricted stock units, and shares issuable to Philips - shares	581	581
Dilutive effect of stock options, restricted stock units, and shares issuable to Philips - per share amount	$ 0.00	$ (0.01)
Diluted EPS - net income	$ 25,078	$ 27,256
Diluted EPS - shares	42,772	42,136
Diluted EPS - per share amount	$ 0.59	$ 0.65