Derivative Instruments (Details) € in Millions	1 Months Ended	3 Months Ended		9 Months Ended		24 Months Ended
	Apr. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2011 USD ($) instrument	Mar. 31, 2018 EUR (€)
Derivative [Line Items]
Amortization of interest expense				$ 1,013,000	$ 998,000
Amount to be recognized from hedged transactions within 12 months, approximate				$ 6,200,000
Foreign currency transaction gain		$ 0
Switzerland
Derivative [Line Items]
Stamp duty expense	$ 2,200,000
Other (Income) Expense Net
Derivative [Line Items]
Foreign currency transaction loss			$ 0		900,000
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						$ 68,900,000
Term of amortized interest expense, years						10 years
Foreign currency exchange contracts
Derivative [Line Items]
Derivative, notional amount | €							€ 180
Cash received from settlement of contracts					6,600,000
Foreign currency exchange contracts | Other (Income) Expense Net
Derivative [Line Items]
Gain (loss) on derivatives			$ 0		$ 900,000