Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Activities:
Net income (loss)	$ (589)	$ 10,196
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	5,289	5,241
Stock-based compensation	1,747	1,950
Bad debt expense (recovery), net	(132)	51
Deferred income taxes	(1,022)	706
Changes in operating assets and liabilities:
Accounts receivable, net	(820)	20,446
Contract assets and liabilities, net	(16,647)	(19,614)
Inventories	(707)	(2,095)
Income taxes	(1,231)	127
Prepaid expenses and other current assets	2,542	2,847
Accounts payable	3,908	(5,602)
Accrued liabilities	(9,119)	(5,163)
Other, net	(1,298)	(1,672)
Net cash provided by (used in) operating activities	(18,079)	7,418
Investing Activities:
Purchases of short-term investments	(15,835)	0
Maturities of short-term investments	15,788	6,146
Purchases of property, plant and equipment, net	(1,590)	(3,469)
Proceeds from life insurance policies	474	0
Net cash provided by (used in) investing activities	(1,163)	2,677
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)
Shares withheld in lieu of employee tax withholding	(632)	(611)
Dividends paid	(6,063)	(6,028)
Net cash used in financing activities	(7,095)	(7,039)
Net increase (decrease) in cash and cash equivalents	(26,337)	3,056
Effect of exchange rate changes on cash and cash equivalents	214	(1,124)
Cash and cash equivalents at beginning of period	160,216	118,639
Cash and cash equivalents at end of period	$ 134,093	$ 120,571