Derivative Instruments (Details) $ in Thousands	3 Months Ended		24 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2011 USD ($) instrument	Dec. 31, 2018 EUR (€)
Derivative [Line Items]
Amortization of interest expense	$ 335	$ 332
Amount to be recognized from hedged transactions within 12 months, approximate	$ 6,300
Other (Income) Expense Net
Derivative [Line Items]
Gain (loss) on derivatives		1,200
Foreign currency transaction loss		$ 1,200
4.20% Senior Notes, due December 2021
Derivative [Line Items]
Interest rate on senior notes			4.20%
4.50% 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
Term of amortized interest expense, years			10 years
Foreign currency exchange contracts
Derivative [Line Items]
Derivative, notional amount | €				€ 180,000,000