Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Net sales	$ 715,440	$ 730,471	$ 726,044
Contract assets, net	93,771	94,302
Inventories, net	147,148	135,296
Cost of sales	445,045	458,311	437,998
Income tax expense	17,175	13,510	20,388
Deferred tax liabilities	73,560	60,715
Accrued other expenses	52,513	49,891
Accumulated Other Comprehensive Income (Loss), Net of Tax	(2,161)	(3,657)
Net earnings	63,496	99,411	81,039
Effect of deferred taxes on tax provision	(3,041)	(2,785)	61
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	(2,200)
Research and Development Expense	15,400	13,300	12,100
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			5,167
Retained Earnings
Net earnings	$ 63,496	99,411	81,039
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			5,167
Maximum
Property, Plant and Equipment, Useful Life	7 years
Maximum | Building [Member]
Property, Plant and Equipment, Useful Life	40 years
Maximum | Machinery and Equipment [Member]
Property, Plant and Equipment, Useful Life	10 years
Maximum | Office Furniture And Equipment [Member]
Property, Plant and Equipment, Useful Life	10 years
Minimum
Property, Plant and Equipment, Useful Life	3 years
Minimum | Building [Member]
Property, Plant and Equipment, Useful Life	10 years
Minimum | Machinery and Equipment [Member]
Property, Plant and Equipment, Useful Life	3 years
Minimum | Office Furniture And Equipment [Member]
Property, Plant and Equipment, Useful Life	3 years
A&D Segment | AS Adjusted
Net sales	$ 2,400
Inventories, net	900
Income tax expense	800
Deferred tax liabilities	200
Accrued other expenses	600
Net earnings	$ 2,500
Basic and diluted earnings per share	$ 0.10
Effect of deferred taxes on tax provision		2,600
USG Segment
Percentage of segment revenues recognized when services are performed or when products are delivered	75.00%
Percentage of consolidated revenues recognized when services are performed or when products are delivered	21.00%
Percentage Of Segment Revenues Recognized On Straight Line Basis	25.00%
Percentage Of Consolidated Revenues Recognized On Straight Line Basis	7.00%
Test Segment
Percentage of segment revenues recognized when services are performed or when products are delivered	20.00%
Percentage of consolidated revenues recognized when services are performed or when products are delivered	6.00%
Percentage of segment revenues recorded under percentage of completion method	80.00%
Percentage of consolidated revenues recorded under percentage of completion method	22.00%
Software Contract [Member]
Percentage of segment revenues recognized when services are performed or when products are delivered	8.00%
Percentage of consolidated revenues recognized when services are performed or when products are delivered	2.00%
Aero space Defense [Member]
Percentage of segment revenues recognized when services are performed or when products are delivered	43.00%
Percentage of consolidated revenues recognized when services are performed or when products are delivered	19.00%
Percentage of segment revenues recorded over time	57.00%
Percentage of consolidate revenues recorded over time	25.00%
A&D
Net sales	$ 314,824	$ 351,876	$ 325,700