Revenue Recognition - Narrative (Details) $ in Millions	3 Months Ended
	Dec. 31, 2018 USD ($) segment	Oct. 01, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Number of operating segments | segment	2
Contract with customer, liability, revenue recognized	$ 115.0
Retained earnings
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Adoption of accounting standard			$ 6.1	$ 0.0
Retained earnings | Impact of Adoption | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Adoption of accounting standard		$ 6.1