Share Based Compensation Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Shares
Outstanding, September 30, 2016	500,000	0
Converted on October 1, 2016		500,000
Granted	0	0
Exercised	0	0
September 30, 2017	500,000	500,000
Weighted Average Exercise Price
Outstanding, September 30, 2016	$ 18.55	$ 0.00
Converted on October 1, 2016		18.37
Granted	0.00	0.00
Exercised	0.00	0.00
September 30, 2017	$ 18.66	$ 18.55
Weighted average remaining contractual terms, options outstanding	4 years 8 months 29 days	5 years 7 months
Aggregate intrinsic value, options outstanding	$ 7.9	$ 9.6
Weighted average remaining contractual terms, options exercisable	4 years 8 months 29 days	5 years 7 months
Aggregate intrinsic value, options exercisable	$ 7.9	$ 9.3