Summary of Significant Accounting Policies (Property, Equipment and Improvements, Net) (Details)	12 Months Ended
	Sep. 30, 2021
Furniture and fixtures, purchases software and other equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, equipment and improvements depreciation life	3 years
Furniture and fixtures, purchases software and other equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, equipment and improvements depreciation life	10 years
Building Improvements and buildings | Minimum
Property, Plant and Equipment [Line Items]
Property, equipment and improvements depreciation life	10 years
Building Improvements and buildings | Maximum
Property, Plant and Equipment [Line Items]
Property, equipment and improvements depreciation life	39 years