Annual report pursuant to Section 13 and 15(d)

Business and summary of significant accounting policies - Cash, Goodwill and Long-lived Assets (Details)

v3.10.0.1
Business and summary of significant accounting policies - Cash, Goodwill and Long-lived Assets (Details) - USD ($)
12 Months Ended
Jul. 01, 2018
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2016
Property and Equipment        
Goodwill, impairment loss $ 0 $ 0    
Restricted cash   7,300,000 $ 13,500,000  
Impairment of long-lived assets held-for-use   $ 0 $ 0 $ 0
Buildings | Maximum        
Property and Equipment        
Estimated useful lives   39 years    
Office furniture and equipment. | Maximum        
Property and Equipment        
Estimated useful lives   7 years    
Software development costs. | Minimum        
Property and Equipment        
Estimated useful lives   3 years    
Software development costs. | Maximum        
Property and Equipment        
Estimated useful lives   8 years