Income Taxes (Composition of Deferred Income Taxes) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Deferred tax assets:
Defined benefit plans, other postretirement	$ 6,844	$ 11,947
Foreign net operating loss carryforwards	6,071	4,707
Inventory	23,549	29,444
Deferred and stock-based compensation	39,903	37,693
Defined benefit plans, pension	2,187	1,148
Deferred revenue	60,177	92,426
Other reserves	10,154	10,850
Tax credits and incentives	12,512	9,769
Other	9,887	7,700
Valuation allowance	(4,522)	(3,714)
Total deferred tax assets, net of valuation allowance	166,762	201,970
Deferred tax liabilities:
Goodwill and intangibles - net	(231,223)	(103,781)
Property, plant and equipment	(85,459)	(109,229)
Other	(4,425)	(2,418)
Total deferred tax liabilities	(321,107)	(215,428)
Net deferred tax liabilities	$ (154,345)	$ (13,458)