Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Accrued Liabilities [Line Items]
Salaries and other member benefits	$ 43,844	$ 91,285
Warranties	13,017	13,597	$ 15,528	$ 15,993
Interest payable	5,392	9,626
Current portion of acquired performance obligations and unfavorable contracts	1,627	1,627
Accrued retirement benefits	2,379	2,413
Current portion of deferred income from JV formation (Note 4)	6,439	6,451
Deferred revenues	3,568	4,625
Taxes, other than income	10,934	14,401
Other	10,341	9,704
Accrued liabilities	98,785	155,072
Loss Reserve On Contractual Lease Commitments [Member]
Accrued Liabilities [Line Items]
Current portion of loss reserve	$ 1,244	$ 1,343