Detail of Certain Balance Sheet Accounts (Tables)

12 Months Ended

Sep. 30, 2017

Detail Of Certain Balance Sheet Accounts [Abstract]

Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]

	Years Ended September 30,
	2017		2016
Balance at beginning of period	$	736	$	842
Additions to costs and expenses		294		360
Deductions for uncollectible receivables written off, net of recoveries		(380)		(466)
Balance at end of period	$	650	$	736

Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]

	Years Ended September 30,
	2017		2016
Accounts payable, trade	$	63,246	$	64,963
Accrued compensation and benefits		33,561		26,827
Accrued insurance liabilities		6,204		5,464
Other accrued expenses		17,699		11,568
	$	120,710	$	108,822

Contracts In Progresstable [Text Block]

	Years Ended September 30,
	2017		2016
Costs incurred on contracts in progress	$	486,950	$	409,075
Estimated earnings		55,606		48,618
		542,556		457,693
Less--Billings to date		(559,036)		(466,368)
Net contracts in progress	$	(16,480)	$	(8,675)
Costs and estimated earnings in excess of billings		13,438		15,554
Less--Billings in excess of costs and estimated earnings		(29,918)		(24,229)
Net contracts in progress	$	(16,480)	$	(8,675)

Schedule of Other Assets, Noncurrent [Table Text Block]

	Years Ended September 30,
	2017		2016
Executive Savings Plan assets		641		599
Securities and equity investments		558		919
Other		2,583		2,192
Total	$	3,782	$	3,710

Schedule of Cost Method Investments [Table Text Block]

	Years Ended September 30,
	2017		2016
Carrying value	$	558	$	919
Unrealized gains		171		159
Fair value	$	729	$	1,078