Earnings Per Share - Schedule of Earnings Per Share, Basic and Dilutive (Details) shares in Thousands	12 Months Ended
	Sep. 30, 2017 shares	Sep. 30, 2016 shares	Sep. 30, 2015 shares
Earnings Per Share [Abstract]
Basic shares	31,952	31,798	27,628
Shares issued upon conversion of TEUs			4,069
Shares issuable upon vesting of stock awards	433	5	75
Shares issuable upon exercise of options	41
Diluted shares	32,426	31,803	31,772
Senior Notes | Tangible Equity Units
Debt Instrument [Line Items]
Number of convertible equity instruments	5,200