Supplemental Statements of Cash Flows Information (Schedule of Cash Flow Supplemental Disclosures) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Supplemental Statements of Cash Flows Information
Interest paid, net of amounts capitalized	$ 27,922	$ 26,627	$ 25,665
Income taxes paid	66,477	52,355	52,705
Income tax refunds received	2,303	6,336	3,183
Purchases of property, plant and equipment on account	13,437	5,345	6,065
Common shares issued from treasury for benefit plans (Note 17)	11,193	9,780	9,335
Notes receivable from municipalities for economic development incentives	6,596	8,114	0
Cashless exercise of stock options	1,286	2,645	0
Settlement of receivable through cashless acquisition of treasury shares in connection with the cashless exercise of stock options	$ 1,736	$ 3,447	$ 0