Quarterly report pursuant to Section 13 or 15(d)

Debt (Details)

v3.4.0.3
Debt (Details)
CAD in Millions
6 Months Ended
Mar. 31, 2016
USD ($)
period
letter_of_credit
Mar. 31, 2016
CAD
period
letter_of_credit
Mar. 09, 2015
USD ($)
Credit Agreement Expiring January 2020      
Debt Instrument [Line Items]      
Maximum borrowing capacity     $ 400,000,000
Total leverage ratio (less than) 1    
Interest paid $ 1,700,000    
Credit Agreement Expiring January 2020 | U.S Dollar Borrowings      
Debt Instrument [Line Items]      
Amount borrowed 281,500,000    
Credit Agreement Expiring January 2020 | Canadian Dollar Borrowings      
Debt Instrument [Line Items]      
Amount borrowed $ 3,700,000 CAD 4.8  
Credit Agreement Expiring January 2020 | Maximum      
Debt Instrument [Line Items]      
Leverage ratio 2.5    
Dividend payment restriction ratio (less than) 2.5    
Swingline Loans      
Debt Instrument [Line Items]      
Maximum borrowing capacity     5,000,000
Letters of Credit      
Debt Instrument [Line Items]      
Maximum borrowing capacity     $ 30,000,000
Number of letters of credit issued | letter_of_credit 3 3  
Outstanding borrowings $ 700,000    
Atlantic Innovation Fund of Canada      
Debt Instrument [Line Items]      
Amount borrowed 800,000 CAD 1.1  
Interest expense, debt $ 0    
Number of remaining quarterly installments | period 25 25  
Letters of Credit (Other than Revolving Credit Agreement)      
Debt Instrument [Line Items]      
Number of letters of credit issued | letter_of_credit 2 2  
Outstanding borrowings $ 3,000,000