Financial Instruments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2017 USD ($) Country	Apr. 23, 2017 USD ($)	Dec. 31, 2016 USD ($)
Derivative [Line Items]
Fair value of contingent consideration		$ 750,000,000
Commercial Paper
Derivative [Line Items]
Commercial paper borrowings outstanding	$ 0		$ 0
Five Year Credit Facility Expiring In November 2021
Derivative [Line Items]
Line of credit facility, borrowing capacity	$ 1,000,000,000
Line of credit facility, expiration date	2021-11
Line of credit facility, term, in years	5 years
National Healthcare Systems and Private Sector Customers | Spain, Italy, Greece, and Portugal
Derivative [Line Items]
Accounts receivable, net	$ 44,300,000
Accounts receivable greater than 365 days past due	$ 2,500,000
The number of countries in Europe in which certain collection risks exist | Country	4
Medicon Inc | Other Long-term Liabilities
Derivative [Line Items]
Liability for deferred future payments for business combinations	$ 41,500,000		39,500,000
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Derivative [Line Items]
Fair value of contingent consideration	14,100,000		14,900,000
Fair Value, Inputs, Level 2
Derivative [Line Items]
Fair value of long-term debt including current maturities	1,707,900,000		1,688,000,000
Fair Value, Inputs, Level 2 | Forward currency contracts | Fair Value, Measurements, Recurring
Derivative [Line Items]
Fair values of forward currency contracts	9,700,000		8,600,000
Fair Value, Inputs, Level 2 | Medicon Inc
Derivative [Line Items]
Liability for deferred future payments for business combinations	54,800,000		52,300,000
Foreign Exchange Contract
Derivative [Line Items]
Notional value of derivative contracts	$ 208,400,000		$ 243,200,000