Supplemental Statements of Cash Flows Information (Schedule of Cash Flow Supplemental Disclosures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Supplemental Statements of Cash Flows Information
Interest paid, net of amounts capitalized	$ 27,752	$ 34,500	$ 32,608
Income taxes paid	33,926	99,468	51,218
Income tax refunds received	997	2,350	689
Purchases of property, plant and equipment on account	17,327	10,705	23,966
Property, plant and equipment acquired by capital lease	0	1,653	0
Common shares issued from treasury stock to settle employee liabilities	1,767	0	0
Common shares issued from treasury stock for benefit plans	14,014	13,999	12,574
Cashless exercise of stock options	$ 1,473	$ 753	$ 1,532