Subsequent Events - Litigation Settlements (Details) $ in Millions	1 Months Ended	9 Months Ended
	Oct. 26, 2018 USD ($) lawsuit	Sep. 30, 2018 USD ($) lawsuit
Subsequent Event [Line Items]
Litigation settlement payment | $		$ 217.5
Opt-Out Actions [Member]
Subsequent Event [Line Items]
Number of claims | lawsuit		13
Opt-Out Actions [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Number of settled litigations | lawsuit	12
Litigation settlement payment | $	$ 127.5