Annual report pursuant to Section 13 and 15(d)

Debt - Narrative (Details)

v3.19.3
Debt - Narrative (Details)
$ in Millions
12 Months Ended
Sep. 30, 2019
USD ($)
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Sep. 30, 2019
CAD ($)
period
Sep. 30, 2019
USD ($)
period
Debt Instrument [Line Items]          
Interest expense $ 2,957,000 $ 1,000,000 $ 2,162,000    
Interest paid $ 2,500,000 $ 600,000 $ 2,000,000.0    
United States          
Debt Instrument [Line Items]          
Outstanding borrowings         $ 3,200,000
Credit Agreement          
Debt Instrument [Line Items]          
Leverage ratio 2.50        
Debt instrument, covenant, actual consolidated leverage ratio (less than) 1.0        
Credit Agreement | Swingline | Line of Credit          
Debt Instrument [Line Items]          
Maximum borrowing capacity         5,000,000
Credit Agreement | Letters of credit | Line of Credit          
Debt Instrument [Line Items]          
Maximum borrowing capacity         50,000,000
Credit Agreement | Revolving Credit Facility | Line of Credit          
Debt Instrument [Line Items]          
Maximum borrowing capacity         400,000,000
Credit Agreement | Minimum          
Debt Instrument [Line Items]          
Line of credit facility, unused capacity, commitment fee percentage 0.125%        
Credit Agreement | Minimum | Base Rate          
Debt Instrument [Line Items]          
Basis spread on variable rate (as a percent) 0.00%        
Credit Agreement | Minimum | Eurocurrency Rate          
Debt Instrument [Line Items]          
Basis spread on variable rate (as a percent) 1.00%        
Credit Agreement | Minimum | Index Rate          
Debt Instrument [Line Items]          
Basis spread on variable rate (as a percent) 1.00%        
Credit Agreement | Maximum          
Debt Instrument [Line Items]          
Line of credit facility, unused capacity, commitment fee percentage 0.275%        
Credit Agreement | Maximum | Base Rate          
Debt Instrument [Line Items]          
Basis spread on variable rate (as a percent) 0.75%        
Credit Agreement | Maximum | Eurocurrency Rate          
Debt Instrument [Line Items]          
Basis spread on variable rate (as a percent) 1.75%        
Credit Agreement | Maximum | Index Rate          
Debt Instrument [Line Items]          
Basis spread on variable rate (as a percent) 1.75%        
Atlantic Innovation Fund of Canada          
Debt Instrument [Line Items]          
Borrowings       $ 0.5 $ 400,000
Interest expense $ 0        
Number of remaining quarterly installments | period       11 11