Financing Arrangments-Interest (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2014	Jun. 30, 2013	Jun. 29, 2014	Jun. 30, 2013
1% Sr. Convertible Notes due 2013 [Member]
Interest Cost Recognized For Convertible Notes
Contractual interest coupon		$ 1,162		$ 3,481
Amortization of bond issuance costs		318		1,014
Amortization of bond discount		6,964		21,022
Total interest cost recognized		8,444		25,517
1.5% Sr. Convertible Notes due 2017 [Member]
Interest Cost Recognized For Convertible Notes
Contractual interest coupon	3,750	3,750	7,500	7,500
Amortization of bond issuance costs	666	666	1,333	1,333
Amortization of bond discount	10,498	9,802	20,690	19,321
Total interest cost recognized	14,914	14,218	29,523	28,154
0.5% Sr. Convertible Notes due 2020 [Member]
Interest Cost Recognized For Convertible Notes
Contractual interest coupon	1,875		3,750
Amortization of bond issuance costs	638		1,297
Amortization of bond discount	10,627		21,398
Total interest cost recognized	$ 13,140		$ 26,445