Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net income (loss)	$ (364)	$ 2,775
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	2,630	2,597
Stock-based compensation	894	982
Bad debt expense (recovery)	(19)	42
Deferred income taxes	(82)	(126)
Changes in operating assets and liabilities:
Accounts receivable, net	(6,249)	11,844
Contract assets and liabilities, net	(4,955)	1,474
Inventories	244	(3,054)
Income taxes	267	216
Prepaid expenses and other current assets	166	498
Accounts payable	(7,387)	(5,457)
Accrued liabilities	(10,087)	(10,128)
Other, net	(234)	445
Net cash provided by (used in) operating activities	(25,176)	2,108
Investing Activities:
Purchases of short-term investments	(3,924)	0
Maturities of short-term investments	7,847	6,146
Purchases of property, plant and equipment, net	(961)	(2,402)
Net cash provided by investing activities	2,962	3,744
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)
Shares withheld in lieu of employee tax withholding	(632)	(611)
Dividends paid	(3,028)	(3,013)
Net cash used in financing activities	(4,060)	(4,024)
Net increase (decrease) in cash and cash equivalents	(26,274)	1,828
Effect of exchange rate changes on cash and cash equivalents	74	499
Cash and cash equivalents at beginning of period	160,216	118,639
Cash and cash equivalents at end of period	$ 134,016	$ 120,966