Debts and Letters of Credit (Details) (USD $) In Millions, except Per Share data, unless otherwise specified			1 Months Ended	3 Months Ended		3 Months Ended					3 Months Ended			1 Months Ended	3 Months Ended				3 Months Ended
	Sep. 29, 2012 letter	Jun. 30, 2012	Jan. 31, 2012 Revolving Credit Facility	Sep. 29, 2012 Revolving Credit Facility	Jan. 20, 2012 Revolving Credit Facility	Sep. 29, 2012 Revolving Credit Facility Alternate base rate	Sep. 29, 2012 Revolving Credit Facility Adjusted LIBOR rate	Sep. 29, 2012 Maximum Revolving Credit Facility	Sep. 29, 2012 Maximum Revolving Credit Facility Alternate base rate	Sep. 29, 2012 Maximum Revolving Credit Facility Adjusted LIBOR rate	Sep. 29, 2012 Minimum Revolving Credit Facility	Sep. 29, 2012 Minimum Revolving Credit Facility Alternate base rate	Sep. 29, 2012 Minimum Revolving Credit Facility Adjusted LIBOR rate	Jun. 30, 2006 1% senior convertible notes	Sep. 29, 2012 1% senior convertible notes	Oct. 01, 2011 1% senior convertible notes	Jun. 30, 2012 1% senior convertible notes	Jun. 05, 2006 1% senior convertible notes	Sep. 29, 2012 1% senior convertible notes Maximum
Debt details
Convertible Debt															$ 249.9		$ 292.8
Short-term debt	249.9	292.8
Interest rate on Senior convertible notes (as a percent)															1.00%	1.00%		1.00%
Aggregate principal amount of convertible debt																		425.0
Proceeds from issuance of convertible notes after issuance costs																		415.9
Conversion price of convertible debt (in dollars per share)															$ 30.30
Percentage of principal amount that the holder of the note may require the entity to repurchase the debt instrument on May 15, 2013, 2016, and 2021															100.00%
Percentage of principal amount that the holder of the note may require the entity to repurchase due to certain fundamental changes undergone by the entity															100.00%
Percentage of principal amount at which the entity may redeem some or all of the notes on or after May 20, 2013															100.00%
Discount rate used to calculate the carrying value of the liability component of the convertible debt (as a percent)																		8.10%
Variable rate basis on which discount rate is based						Base rate	LIBOR							7-year swap
Carrying value of the liability component of convertible debt															266.5
Carrying value of the equity component of convertible debt															158.5
Remaining term of convertible notes																			1 year
Deferred finance costs					1.9													9.1
Liability component, debt issuance cost																		5.7
Equity component, debt issuance cost																		3.4
Principal amount of debt repurchased															50.0
Cash paid for repurchase of debt															49.8
Loss on repurchase of Convertible Notes															2.1
Carrying amounts of the liability and equity components:
Carrying amount of equity component, net of equity issuance cost															157.6		158.3
Principal amount of 1% senior convertible note															261.0		311.0
Unamortized discount of liability component															(11.1)		(18.2)
Fair market value of convertible debt															259.9		307.3
Fair value of the bond parity derivatives															0		0
Effective interest rate and interest expense for the contractual interest and the accretion of debt discount:
Effective interest rate (as a percent)															8.10%	8.10%
Interest expense-contractual interest															0.7	0.8
Accretion of debt discount															4.2	4.9
Variable interest rate base						Base rate	LIBOR							7-year swap
Credit facility term			5 years
Maximum borrowing capacity under the credit agreement					250.0
Maximum borrowing capacity optional expansion				100
Percentage points added to the reference rate									2.00%	3.00%		0.75%	1.75%
Commitment fee on the unused portion of the credit facility (as a percent)								0.50%			0.25%
Minimum cash and permitted investments agreed to be maintained under the terms of revolving credit facility				200
Period of amortization of interest expenses capitalized				5 years
Outstanding balance				0
Unamortized portion of debt issuance cost				1.6											0.4
Outstanding Letters of Credit
Number of standby letters of credit	15
Letters of credit outstanding	$ 35.2