Supplemental Statements of Cash Flows Information (Schedule of Cash Flow Supplemental Disclosures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Supplemental Statements of Cash Flows Information
Interest paid, net of amounts capitalized	$ 29,677	$ 27,752	$ 34,500
Income taxes paid	44,831	33,926	99,468
Income tax refunds received	1,976	997	2,350
Purchases of property, plant and equipment on account	11,982	17,327	10,705
Property, plant and equipment acquired by capital lease	0	0	1,653
Common shares issued from treasury stock to settle employee liabilities	0	1,767	0
Common shares issued from treasury stock for benefit plans	14,741	14,014	13,999
Cashless exercise of stock options	$ 0	$ 1,473	$ 753