Derivative Instruments, Foreign Exchange Contracts (Details) - Foreign Exchange Contract [Member] ¥ in Millions, $ in Millions	3 Months Ended
Mar. 31, 2018 JPY (¥)	Mar. 31, 2018 AUD ($)	Dec. 31, 2016 JPY (¥)	Dec. 31, 2016 EUR (€)	Dec. 31, 2016 AUD ($)
Derivative [Line Items]
Foreign exchange contract outstanding	¥ 162.5	$ 0.2	¥ 162.5	€ 24,000	$ 0.2
Expiration date of contract	Dec. 31, 2018

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