Quarterly report pursuant to Section 13 or 15(d)

Debt (Details)

v3.10.0.1
Debt (Details)
9 Months Ended
Jun. 30, 2018
USD ($)
letter_of_credit
Jun. 30, 2017
USD ($)
Credit Agreement Expiring 2022    
Debt Instrument [Line Items]    
Interest paid $ 100,000 $ 1,900,000
Letters of Credit    
Debt Instrument [Line Items]    
Number of letters of credit issued | letter_of_credit 2  
Outstanding borrowings $ 700,000  
Letters of Credit (Other than Revolving Credit Agreement)    
Debt Instrument [Line Items]    
Number of letters of credit issued | letter_of_credit 2  
Outstanding borrowings $ 3,000,000  
Line of Credit | Credit Agreement Expiring 2022 | Revolving Credit Facility    
Debt Instrument [Line Items]    
Maximum borrowing capacity 400,000,000  
Line of Credit | Credit Agreement Expiring 2022 | Bridge Loan    
Debt Instrument [Line Items]    
Maximum borrowing capacity 5,000,000  
Line of Credit | Credit Agreement Expiring 2022 | Letters of Credit    
Debt Instrument [Line Items]    
Maximum borrowing capacity $ 50,000,000