Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015
Salaries and other member benefits	$ 37,947		$ 87,197
Warranties	15,041	$ 15,528	15,993	$ 15,553	$ 13,370	$ 13,741
Interest payable	9,091		9,071
Current portion of acquired performance obligations and unfavorable contracts	2,393		2,910
Accrued retirement benefits	2,503		2,505
Current portion of deferred income from JV formation (Note 4)	6,352		6,552
Deferred revenues	5,385		5,779
Taxes, other than income	13,890		14,580
Other	11,536		10,200
Accrued liabilities	105,978		156,627
Loss Reserve On Contractual Lease Commitments [Member]
Current portion of loss reserve	$ 1,840		$ 1,840