Stock-Based Compensation - Restricted Stock Units Granted (Details) - shares	9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	1,008,570	1,679,591
Restricted Stock, Time Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	377,213	734,250
Board of Director Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	43,019	85,091
Restricted Stock, Performance Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	588,338	860,250