Earnings per Share - EPS Reconciliation (Details) - USD ($)	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income	$ 18.2	$ (6.9)
Less: Net income allocated to participating securities	(0.3)	0.0
Net income allocated to common shareholders	$ 0	$ 0
Weighted average number of common shares outstanding	18,659,748	18,419,072
Dilutive potential common shares outstanding:
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	333,298	0
Diluted weighted-average shares	18,993,046	18,419,072