Long Term Debt (Narrative) (Details) (USD $)	6 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Feb. 28, 2015	Oct. 31, 2001
Line Of Credit Facility [Line Items]
Balance in the restricted sinking fund	$ 200,000
U.S. Revolver
Line Of Credit Facility [Line Items]
Revolving credit facility		75,000,000
Revolving credit interest rate	The interest rate for amounts outstanding under the Amended Credit Agreement for the U.S. Revolver is a floating rate based upon the higher of the Federal Funds Rate plus 0.5%, the bank’s prime rate, or the Eurocurrency rate plus 1.00%.
Outstanding letters of credit	18,000,000
Amount of credit facility remaining borrowing capacity	57,000,000
Credit facility expiration date	Dec. 31, 2018
Revolving credit facility, current borrowing capacity	0
Percentage of voting capital stock pledged as collateral	100.00%
Non-domestic subsidiaries of voting capital stock	65.00%
U.S. Revolver | Maximum
Line Of Credit Facility [Line Items]
Basis spread on variable rate	1.75%
U.S. Revolver | Federal Funds Rate
Line Of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
U.S. Revolver | Eurocurrency Rate
Line Of Credit Facility [Line Items]
Basis spread on variable rate	1.00%
Canadian Revolver
Line Of Credit Facility [Line Items]
Revolving credit facility			7,900,000
Credit facility expiration date	Feb. 28, 2015
Canadian Revolver | Maximum
Line Of Credit Facility [Line Items]
Basis spread on variable rate	1.75%
Canadian Revolver | Minimum
Line Of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
Industrial Development Revenue Bonds
Line Of Credit Facility [Line Items]
Borrowings				8,000,000
Reimbursement agreement requires annual redemptions	$ 400,000
Interest rate	0.16%