Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Stock Based Compensation (Details)	12 Months Ended
	Sep. 30, 2018
Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining vesting period	1 year
Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining vesting period	5 years
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years