Derivative Financial Instruments - Additional Information (Details) € in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) item	Sep. 30, 2017 USD ($)	Sep. 30, 2018 EUR (€)	Dec. 31, 2017 USD ($)
Derivative [Line Items]
Foreign currency unrealized losses expected to be reclassified into earnings over next twelve months	$ (700,000)		$ (700,000)
3.95% senior unsecured notes due 2027
Derivative [Line Items]
Proceeds from issue of senior notes in settlement of derivatives			$ 10,000,000
Debt instrument, interest rate	3.95%		3.95%		3.95%	3.95%
Interest Rate Swap Agreements
Derivative [Line Items]
Derivative fixed interest rate (as a percent)	0.51%		0.51%		0.51%
Carrying value / fair value of derivative liabilities included in other liabilities	$ 300,000		$ 300,000			$ 400,000
Interest Rate Swap Agreements | U.S. dollars
Derivative [Line Items]
Variable Rate Basis			LIBOR
Interest Rate Swap Agreements | EUR
Derivative [Line Items]
Variable Rate Basis			Euribor
Swaps maturing September 2019
Derivative [Line Items]
Average fixed interest rate (as a percent)	1.09%		1.09%		1.09%
Interest Rate Swap Final Maturity Period One
Derivative [Line Items]
Final maturity date of swap amortization			Jun. 30, 2023
Interest Rate Swap Final Maturity Period Two
Derivative [Line Items]
Final maturity date of swap amortization			Jun. 30, 2024
Treasury Lock | Interest Lock Agreement | 3.95% senior unsecured notes due 2027
Derivative [Line Items]
Percentage of reduction in effective interest rate on senior notes			0.25%
Foreign Currency Forward Exchange Contracts
Derivative [Line Items]
Number of credit contingency features | item			0
Foreign Currency Forward Exchange Contracts | Cash Flow Hedging
Derivative [Line Items]
Gains (losses) in other comprehensive income, effective portion	$ (600,000)	$ 9,700,000	$ (13,100,000)	$ 31,700,000
Designated as Hedging Instrument | Interest Rate Swap Agreements
Derivative [Line Items]
Floating rate obligation	50,000,000		50,000,000		€ 52.9
Carrying value / fair value of derivative assets included in other assets	800,000		800,000			800,000
Designated as Hedging Instrument | Foreign Currency Forward Exchange Contracts
Derivative [Line Items]
Carrying value / fair value of derivative assets included in other assets	4,800,000		4,800,000			14,700,000
Carrying value / fair value of derivative liabilities included in other liabilities	8,500,000		8,500,000			2,800,000
Notional amount	408,600,000		408,600,000			285,400,000
Gains (losses) in other comprehensive income, effective portion	(300,000)	7,200,000	(9,700,000)	23,500,000
Designated as Hedging Instrument | Foreign Currency Forward Exchange Contracts | Cash Flow Hedging
Derivative [Line Items]
Net gain (loss) recognized in gross margin	(900,000)	(600,000)	2,500,000	(11,400,000)
Not Designated as Hedging Instrument | Foreign Currency Forward Exchange Contracts
Derivative [Line Items]
Carrying value / fair value of derivative assets included in other assets	500,000		500,000			1,300,000
Carrying value / fair value of derivative liabilities included in other liabilities	100,000		100,000			$ 100,000
Foreign exchange net gains (losses) on derivative contracts not designated as hedges	$ (100,000)	$ 4,000,000	$ (4,100,000)	$ 15,400,000