Commitments and Contingencies (Details)		3 Months Ended
	Jul. 10, 2015 USD ($) ft²	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Feb. 29, 2016 USD ($)	Dec. 31, 2015 USD ($)	Mar. 31, 2014 USD ($)	Mar. 31, 2011 USD ($)
Summarization of principal contractual obligations
Future minimum payments under the non-cancelable operating leases	$ 118,100,000	$ 111,800,000
Rent expense		9,100,000	$ 11,500,000
Lease term, option to extend	20 years
Square feet of leased space | ft²	63,000
Term of lease	10 years
Tenant allowance	$ 6,000,000
Property and equipment, net		1,047,300,000			$ 1,021,000,000
Total purchase commitments		601,600,000
Accrual for estimated carrying charges or obsolete materials charges		19,800,000
Short-term debt		0			299,900,000
Long-term debt, carrying value		2,131,800,000			1,637,500,000
Indemnity-related and service-related escrows		36,100,000
Campus build out commitments		3,500,000
Other contractual obligations		45,500,000
Long-term income taxes payable		190,400,000			$ 187,300,000
Construction in Progress [Member]
Summarization of principal contractual obligations
Property and equipment, net		59,800,000
Fixed Rate Note Due 2019 [Member]
Summarization of principal contractual obligations
Long-term debt, gross		$ 350,000,000		$ 350,000,000
Short-term and Long-term debt, stated interest rate		3.125%		3.125%
Fixed rate note due 2016 [Member]
Summarization of principal contractual obligations
Short-term and Long-term debt, stated interest rate		3.10%
Fixed rate note due 2020 [Member]
Summarization of principal contractual obligations
Long-term debt, gross		$ 300,000,000	$ 300,000,000
Short-term and Long-term debt, stated interest rate		3.30%	3.30%
Fixed rate note due 2021 [Member]
Summarization of principal contractual obligations
Long-term debt, gross		$ 300,000,000					$ 300,000,000
Short-term and Long-term debt, stated interest rate		4.60%					4.60%
Fixed rate note due 2024 [Member]
Summarization of principal contractual obligations
Long-term debt, gross		$ 500,000,000				$ 350,000,000
Short-term and Long-term debt, stated interest rate		4.50%
Fixed rate note due 2025 [Member]
Summarization of principal contractual obligations
Long-term debt, gross		$ 300,000,000	$ 300,000,000
Short-term and Long-term debt, stated interest rate		4.35%	4.35%
Fixed rate note due 2041 [Member]
Summarization of principal contractual obligations
Long-term debt, gross		$ 400,000,000					$ 400,000,000
Short-term and Long-term debt, stated interest rate		5.95%					5.95%
Minimum [Member]
Summarization of principal contractual obligations
Increment for lease extension	5 years
Maximum [Member]
Summarization of principal contractual obligations
Increment for lease extension	10 years