Hedging - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative term	1 month
Foreign currency forward contracts | Not designated as hedging instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative term	1 year
Foreign currency forward contracts | Not designated as hedging instrument | Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of foreign currency forward contract	$ 251.4