Balance Sheet Details (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Sep. 30, 2019
Restricted Cash
Restricted cash	$ 31,700	$ 29,500
Inventories
Finished products	17,840	10,905
Work in process and inventoried costs under long-term contracts	76,229	46,951
Materials and purchased parts	45,583	48,938
Net inventories	139,652	106,794
Costs incurred outside the scope of work or in advance of a contract award	4,700	5,800
General and administrative amounts for certain government contracts remaining in inventory	400	500
Property, Plant and Equipment
Accumulated depreciation and amortization	(171,625)	(160,271)
Property, plant and equipment - net	156,445	144,969
Deferred Compensation Plan
Deferred compensation	10,100	11,000
Carrying value of Rabbi trust to fund deferred compensation liabilities	5,800	5,800
Land and land improvements
Property, Plant and Equipment
Property, plant and equipment, Gross	7,364	7,348
Buildings and improvements
Property, Plant and Equipment
Property, plant and equipment, Gross	48,514	48,191
Machinery and other equipment
Property, Plant and Equipment
Property, plant and equipment, Gross	120,498	107,297
Software
Property, Plant and Equipment
Property, plant and equipment, Gross	110,439	108,526
Leasehold improvements
Property, Plant and Equipment
Property, plant and equipment, Gross	18,719	17,064
Construction and internal-use software development in progress
Property, Plant and Equipment
Property, plant and equipment, Gross	$ 22,536	$ 16,814

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