Income Taxes (Composition of Deferred Income Taxes) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Deferred tax assets:
Defined benefit plans, other postretirement	$ 11,947	$ 13,017
Foreign net operating loss carryforwards	4,707	5,255
Inventory	29,444	27,332
Deferred and stock-based compensation	37,693	34,388
Defined benefit plans, pension	1,148	8,955
Deferred revenue	92,426	92,213
Other reserves	10,850	13,968
Tax credits and incentives	9,769	7,744
Other	7,700	7,411
Valuation allowance	(3,714)	(3,317)
Total deferred tax assets, net of valuation allowance	201,970	206,966
Deferred tax liabilities:
Goodwill and intangibles - net	(103,781)	(99,030)
Property, plant and equipment	(109,229)	(88,986)
Other	(2,418)	(2,533)
Total deferred tax liabilities	(215,428)	(190,549)
Net deferred tax liabilities	$ (13,458)	$ 16,417