Accounts Receivable (Schedule of Accounts Receivable) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for uncollectible customer amounts	$ (3,793)	$ (3,776)
Accounts receivable	331,438	402,182
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross	275,433	367,715
Accounts Receivable from Chinese Financial Institution [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross	$ 59,798	$ 38,243