Derivative Instruments - Narrative (Details)	3 Months Ended		24 Months Ended
	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2011 USD ($) instrument	Mar. 31, 2018 EUR (€)
Derivative [Line Items]
Amortization of interest expense	$ 332,000	$ 329,000
Amount to be recognized from hedged transactions within 12 months, approximate	6,400,000
Other (Income) Expense Net
Derivative [Line Items]
Foreign currency transaction loss	1,200,000	400,000
4.2% Senior Notes, due December 2021
Derivative [Line Items]
Interest rate on senior notes			4.20%
4.5% Senior Notes, due December 2020
Derivative [Line Items]
Interest rate on senior notes			4.50%
Interest Rate Contract
Derivative [Line Items]
Number of instruments held | instrument			2
Interest Rate Exchange Agreement Expiring 2010 and 2011
Derivative [Line Items]
Amortization of interest expense			$ 68,900,000
Term of amortized interest expense, years			10 years
Foreign currency exchange contracts
Derivative [Line Items]
Notional amount | €				€ 180,000,000
Cash received from settlement of contracts	6,600,000.0
Foreign currency exchange contracts | Other (Income) Expense Net
Derivative [Line Items]
Gain on derivatives	$ 1,200,000	$ 400,000