Convertible Senior Notes (Details) (USD $) In Thousands, unless otherwise specified	Apr. 01, 2012	Jan. 01, 2012
Summarized information about equity and liability components of convertible senior notes
Less: current portion of long-term debt	$ (35,025)	$ 0
Long-term debt	780,943	807,369
Conversion option subject to cash settlement	5,100	5,722
0.25% Convertible Senior Notes due 2016 [Member]
Summarized information about equity and liability components of convertible senior notes
Principal amount of convertible notes outstanding	920,000	920,000
Unamortized discount of liability component	(139,057)	(147,034)
Net carrying amount of liability component	780,943	772,966
Less: current portion of long-term debt	0	0
Long-term debt	780,943	772,966
Conversion option subject to cash settlement	0	0
Carrying value of equity component, net of debt issuance cost		155,366
Fair value of outstanding notes (Level 2 measurement)	878,444	725,632
Remaining amortization period of discount on the liability component (in years)	4.0	4.2
0.625% Convertible senior notes due 2014 [Member]
Summarized information about equity and liability components of convertible senior notes
Principal amount of convertible notes outstanding	40,125	40,125
Unamortized discount of liability component	(5,100)	(5,722)
Net carrying amount of liability component	35,025	34,403
Less: current portion of long-term debt	(35,025)	0
Long-term debt	0	34,403
Conversion option subject to cash settlement	5,100	5,722
Carrying value of equity component, net of debt issuance cost	113,413	114,035
Fair value of outstanding notes (Level 2 measurement)	$ 96,826	$ 60,122
Remaining amortization period of discount on the liability component (in years)	1.9	2.1