Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Accrued Liabilities [Abstract]
Salaries and other member benefits		$ 62,352	$ 115,649
Warranties		18,927	27,309	$ 20,156	$ 20,130
Interest payable		5,807	13,808
Accrued retirement benefits		3,608	3,587
Current portion of loss reserve on contractual lease commitments	[1]		1,245
Restructuring charges		255	507
Taxes, other than income		17,763	15,708
Net current contract liabilities (Note 3)		24,961	27,891
Liabilities held for sale (Note 10)		10,186
Other		24,230	22,423
Accrued liabilities		$ 168,089	$ 228,127

[1] See Note 17, Other liabilities, for more information on loss reserve on contractual lease commitments.