Commitments and Contingencies Loss Contingencies (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Jun. 30, 2018
Loss Contingencies [Line Items]
Legal proceedings recorded as a liability under other noncurrent liabilities	$ (4.5)	$ (7.6)
Strack royalty payment litigation [Member]
Loss Contingencies [Line Items]
Damages sought in litigation matter		200.0
Estimated Litigation Liability, Current	17.3	$ 59.6	$ 61.7
Settlement payment	$ 45.8