Operations ans summary of significant accounting policies (Schedule of Accounts Receivable) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Accounts receivable	$ 346,858	$ 381,065
Allowance for uncollectible customer amounts	(7,078)	(8,872)
Trade Accounts Receivable [Member]
Accounts Receivable, Gross	291,584	316,983
Accounts Receivable from Chinese Financial Institution [Member]
Accounts Receivable, Gross	$ 62,352	$ 72,954