Commitments and Contingencies (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Summarization of principal contractual obligations
Future minimum payments under the non-cancelable operating leases	$ 221,300,000
Rent expense	13,000,000	13,700,000
Total purchase commitments	489,700,000
Accrual for estimated carrying charges or obsolete materials charges	20,500,000
Long-term debt, carrying value	1,348,900,000		999,300,000
Long-term debt, gross	1,350,000,000
Indemnity-related and service-related escrows	71,600,000
Campus build out commitments	13,900,000
Other contractual obligations	7,800,000
Long-term income taxes payable	121,700,000		114,400,000
Fixed rate note due 2016 [Member]
Summarization of principal contractual obligations
Long-term debt, gross	300,000,000
Long-term debt, effective interest rate	3.25%
Long-term debt, stated interest rate	3.10%
Fixed rate note due 2021 [Member]
Summarization of principal contractual obligations
Long-term debt, gross	300,000,000
Long-term debt, effective interest rate	4.69%
Long-term debt, stated interest rate	4.60%
Fixed Rate Note Due 2024 [Member]
Summarization of principal contractual obligations
Long-term debt, gross	350,000,000
Long-term debt, effective interest rate	4.63%
Long-term debt, stated interest rate	4.50%
Fixed rate note due 2041 [Member]
Summarization of principal contractual obligations
Long-term debt, gross	$ 400,000,000
Long-term debt, effective interest rate	6.03%
Long-term debt, stated interest rate	5.95%