Derivative Financial Instruments (Narrative) (Details) - Foreign exchange contracts - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional Amount of Foreign Currency Cash Flow Hedge	$ 96.1	$ 95.0
Cash Flow Hedging \| Derivatives designated as hedging instruments
Derivative [Line Items]
Notional Amount of Foreign Currency Cash Flow Hedge	$ 119.9	$ 93.5

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant