Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Deferred tax assets:
Defined benefit plans, other postretirement	$ 6,535	$ 6,844
Foreign net operating loss carryforwards	6,836	6,071
Inventory	51,740	23,549
Stock-based and other compensation	45,839	39,903
Defined benefit plans, pension	11,399	2,187
Deferred revenue net of unbilled receivables	32,310	60,177
Other reserves	11,571	10,154
Tax credits and incentives	13,580	12,512
Other	5,611	9,887
Valuation allowance	(3,638)	(4,522)
Total deferred tax assets, net of valuation allowance	181,783	166,762
Deferred tax liabilities:
Goodwill and intangibles - net	(212,926)	(231,223)
Property, plant and equipment	(97,469)	(85,459)
Other	(4,589)	(4,425)
Total deferred tax liabilities	(314,984)	(321,107)
Net deferred tax liabilities	$ (133,201)	$ (154,345)