Derivative Financial Instruments and Fair Value Measurements (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 EUR (€)	Dec. 31, 2016 USD ($)
Net investment hedges [Abstract]
Translation gain (loss) on net investment hedge	$ (30,400,000)		$ (30,400,000)			$ 24,800,000
Fair value measured on a recurring basis
Assets
Deferred compensation plan assets	95,400,000		95,400,000			86,800,000
Total assets measured at fair value	95,400,000		95,400,000			86,800,000
Liabilities
Foreign currency forward contracts	100,000		100,000			200,000
Total liabilities measured at fair value	100,000		100,000			200,000
Fair value measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Deferred compensation plan assets	95,400,000		95,400,000			86,800,000
Total assets measured at fair value	95,400,000		95,400,000			86,800,000
Liabilities
Foreign currency forward contracts	0		0			0
Total liabilities measured at fair value	0		0			0
Fair value measured on a recurring basis | Significant Other Observable Inputs (Level 2)
Assets
Deferred compensation plan assets	0		0			0
Total assets measured at fair value	0		0			0
Liabilities
Foreign currency forward contracts	100,000		100,000			200,000
Total liabilities measured at fair value	100,000		100,000			200,000
Fair value measured on a recurring basis | Significant Unobservable Inputs (Level 3)
Assets
Deferred compensation plan assets	0		0			0
Total assets measured at fair value	0		0			0
Liabilities
Foreign currency forward contracts	0		0			0
Total liabilities measured at fair value	0		0			0
Euro-denominated notes
Net investment hedges [Abstract]
Translation gain (loss) on net investment hedge	(26,200,000)		(26,200,000)			29,000,000
Forward contracts | Designated as hedging instrument
Net investment hedges [Abstract]
Translation gain (loss) on net investment hedge	(4,200,000)		(4,200,000)			(4,200,000)
Forward contracts | Not designated as hedging instrument
Net investment hedges [Abstract]
Loss associated with forward contracts included in interest and other expenses	0	$ 100,000	0	$ 1,400,000
Fair value | Euro-denominated notes | Significant Other Observable Inputs (Level 2)
Liabilities
Carrying value of long-term debt	929,900,000		929,900,000			831,600,000
Carrying value | Euro-denominated notes
Liabilities
Carrying value of long-term debt	883,200,000		883,200,000			$ 785,200,000
Notes due September 2022 | Euro-denominated notes | Designated as hedging instrument
Net investment hedges [Abstract]
Long-term debt	470,000,000		470,000,000		€ 400,000,000
Notes due June 2018 | Euro-denominated notes | Designated as hedging instrument
Net investment hedges [Abstract]
Long-term debt	$ 413,200,000		$ 413,200,000		€ 350,000,000.0