Stock-Based Compensation - Restricted Stock Units Granted - Tabular Disclosure (Details) - shares	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stocks granted (in shares)	408,827	789,409
Restricted Stock, Time Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stocks granted (in shares)	163,390	327,500
Board of Director Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stocks granted (in shares)	23,867	38,520
Restricted Stock, Performance Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stocks granted (in shares)	221,570	423,389