Financing Arrangements - Additional Information (Detail) (USD $)					1 Months Ended				1 Months Ended					1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended			1 Months Ended	3 Months Ended	1 Months Ended
	Jan. 25, 2013	Apr. 27, 2012	Jan. 25, 2013 Warrant	Apr. 27, 2012 Warrant	Dec. 31, 2012 Revolving Credit Facility Extension	Dec. 21, 2012 Revolving Credit Facility	Dec. 21, 2012 Revolving Credit Facility Minimum	Dec. 21, 2012 Revolving Credit Facility Maximum	Dec. 31, 2012 Revolving Credit Facility Maximum Leverage Ratio	Dec. 31, 2012 Revolving Credit Facility Minimum Interest Coverage Ratio	Dec. 21, 2012 Revolving Credit Facility Foreign Currency Sub Facility	Dec. 21, 2012 Revolving Credit Facility Letter Of Credit Sub Facility	Dec. 21, 2012 Revolving Credit Facility Swingline Subfacility	Dec. 31, 2012 Convertible Notes Payable	Jun. 10, 2008 Convertible Notes Payable	Jan. 25, 2013 Convertible Notes Payable	Jan. 25, 2013 Convertible Notes Payable D	Apr. 27, 2012 Convertible Notes Payable	Jun. 10, 2008 Convertible Notes Payable Equity Component	Jun. 10, 2008 Convertible Notes Payable Liability Component	Dec. 12, 2012 Senior Notes Due 2017 and 2022	Jan. 25, 2013 Senior Notes Due 2017 and 2022	Dec. 12, 2012 Senior Notes due 2017	Dec. 12, 2012 Senior Notes Due 2022
Debt Disclosure [Line Items]
Notes issued, principal amount	$ 2,264,900,000	$ 1,264,900,000													$ 1,265,000,000	$ 1,264,900,000	$ 1,264,900,000	$ 1,264,900,000					$ 750,000,000	$ 250,000,000
Notes issued, interest rate															1.75%								2.00%	3.25%
Notes issued, maturity date																	Jun. 01, 2013						Dec. 15, 2017	Dec. 15, 2022
Debt discounts	27,300,000	62,600,000													248,000,000						5,800,000
Notes issued, issuance costs																					6,900,000
Interest expense																						3,100,000
Note repurchase price, percentage of principal amount of notes																	100.00%				101.00%
Numerator of common stock ratio for convertible notes																31.40	31.40
Denominator of principal amount upon which conversion rate is based																1,000	1,000
Conversion price of notes to shares of common stock	$ 31.85															$ 31.85	$ 31.85
Number of business days after measurement period																	5
Convertible notes, measurement period for conversion, days																	5
Trading price of convertible notes during measurement period, maximum percentage																98.00%
Trading price of convertible notes during measurement period, percentage																130.00%
Convertible notes, conversion threshold price														$ 41.41
Convertible notes, number of trading days during the 30 consecutive trading days ended December 31, 2012 during which common stock price did not exceed the conversion threshold price														20 days
Convertible notes, number of consecutive trading days during which Common stock price did not exceed the conversion threshold price														30 days
Closing price of common stock																36.15	36.15
If converted vale of the Convertible notes exceeded over Principal																	170,900,000
Convertible Notes															1,017,000,000
Effective interest rate															6.31%		6.31%	6.31%
Issuance costs on equity																			5,200,000	21,400,000
Convertible Note Hedge number of shares contracted to sell	31,800,000	31,800,000
Convertible Note Hedge Exercise Price	$ 31.85	$ 31.85
Outstanding warrants, number of shares			39,700,000	39,700,000
Exercise price of warrants			41.28	41.28
Unhedged portion of notes																20.00%	20.00%
Credit facility, amount						250,000,000					100,000,000	50,000,000	10,000,000
Credit facility, term					5 years
Credit facility, increase in facility						$ 100,000,000
Credit facility, number of extensions					2
Credit facility, extensions period					1 year
Credit facility, base rate							0.20%	1.20%
Credit facility, date terminate					Dec. 21, 2017
Covenant Terms									3.0 :1.0	3.5: 1.0