Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Accrued Liabilities
Salaries and other member benefits	$ 91,285	$ 87,197
Warranties	13,597	15,993	$ 13,741	$ 16,916
Interest payable	9,626	9,071
Current portion of acquired performance obligations and unfavorable contracts	1,627	2,910
Accrued retirement benefits	2,413	2,505
Current portion of loss reserve	1,343	1,840
Current portion of deferred income from JV formation (Note 4)	6,451	6,552
Deferred revenues	4,625	5,779
Taxes, other than income	14,401	14,580
Other	9,704	10,200
Accrued liabilities	$ 155,072	$ 156,627