Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Deferred tax assets:
Defined benefit plans, other postretirement	$ 5,364	$ 6,238
Foreign net operating loss carryforwards	2,110	6,106
Inventory	51,011	53,867
Stock-based and other compensation	36,343	35,919
Defined benefit plans, pension		5,624
Deferred revenue net of unbilled receivables	46,002	39,990
Other reserves	10,619	10,119
Tax credits and incentives	22,756	14,340
Lease obligations	5,818	5,764
Other	7,936	9,223
Valuation allowance	(4,138)	(1,833)
Total deferred tax assets, net of valuation allowance	183,821	185,357
Deferred tax liabilities:
Goodwill and intangibles - net	(210,911)	(218,900)
Property, plant and equipment	(105,724)	(107,862)
Right of use assets	(5,497)	(4,837)
Defined benefit plans, pension	(2,837)
Other	(2,722)	(2,673)
Total deferred tax liabilities	(327,691)	(334,272)
Net deferred tax liabilities	$ (143,870)	$ (148,915)