Annual report pursuant to Section 13 and 15(d)

Long-Term Debt and Lines of Credit - Schedule of Long-term Debt, Net of Current Portion (Details)

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Long-Term Debt and Lines of Credit - Schedule of Long-term Debt, Net of Current Portion (Details) - USD ($)
Sep. 30, 2016
Sep. 30, 2015
Dec. 03, 2014
Dec. 02, 2014
Sep. 30, 2014
Debt Instrument [Line Items]          
Long-term debt, net of current portion $ 197,219,000 $ 205,481,000      
Less current portion 4,493,000 4,511,000      
Long-term debt 192,726,000 200,970,000      
Metropolitan Life Insurance Company and New England Life Insurance Company fixed rate term loans in the original principal amount of $125,000,000: the loans bear interest at the rate of 4.15% per annum. The loans are collateralized by real estate and mature in November 2029.          
Debt Instrument [Line Items]          
Long-term debt, net of current portion 105,312,000 111,563,000 $ 125,000,000    
Principal amount $ 125,000,000        
Fixed interest rate 4.15%   4.15%    
Metropolitan Life Insurance Company and New England Life Insurance Company variable rate term loans in the original principal amount of $57,500,000: the variable interest rate was 2.25% per annum at September 30, 2016. The loans are collateralized by real estate and mature in November 2029.          
Debt Instrument [Line Items]          
Long-term debt, net of current portion $ 52,469,000 $ 55,344,000 $ 57,500,000 $ 33,500,000  
Principal amount $ 57,500,000        
Variable interest rate 2.25% 1.80%     2.40%
Metropolitan Life Insurance Company term loan: the loan bears interest at the rate of 5.28% per annum as of September 30, 2016. The loan is secured by real estate and matures in February 2029.          
Debt Instrument [Line Items]          
Long-term debt, net of current portion $ 5,000,000 $ 2,500,000      
Fixed interest rate 5.28%        
Prudential Mortgage Capital Company, LLC fixed rate term loans: the loans bear interest at the rate of 5.35% per annum as of September 30, 2016. The loans are collateralized by real estate and mature in June 2033.          
Debt Instrument [Line Items]          
Long-term debt, net of current portion $ 24,190,000 25,350,000      
Fixed interest rate 5.35%        
Prudential Mortgage Capital Company, LLC fixed rate term loan: the loan bears interest at the rate of 3.85% per annum as of September 30, 2016. The loan is collateralized by real estate and matures in September 2021.          
Debt Instrument [Line Items]          
Long-term debt, net of current portion $ 5,115,000 5,335,000      
Fixed interest rate 3.85%        
Prudential Mortgage Capital Company, LLC fixed rate term loan: the loan bears interest at the rate of 3.45% per annum as of September 30, 2016. The loan is collateralized by real estate and matures in September 2039.          
Debt Instrument [Line Items]          
Long-term debt, net of current portion $ 5,115,000 5,335,000      
Fixed interest rate 3.45%        
Note payable to a financing company secured by equipment and maturing in December 2016.          
Debt Instrument [Line Items]          
Long-term debt, net of current portion $ 18,000 $ 54,000