Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Activities:
Net income (loss)	$ 10,196	$ (1,737)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	5,241	6,460
Stock-based compensation	1,950	1,890
Bad debt expense	51	101
Deferred income taxes	706	(346)
Changes in operating assets and liabilities:
Accounts receivable, net	20,446	12,716
Contract assets and liabilities, net	(19,614)	19,663
Inventories	(2,095)	(3,452)
Income taxes	127	6,198
Prepaid expenses and other current assets	2,847	61
Accounts payable	(5,602)	(7,080)
Accrued liabilities	(5,163)	(7,640)
Other, net	(1,672)	(787)
Net cash provided by operating activities	7,418	26,047
Investing Activities:
Purchases of short-term investments	0	(5,869)
Maturities of short-term investments	6,146	13,088
Purchases of property, plant and equipment, net	(3,469)	(1,963)
Net cash provided by investing activities	2,677	5,256
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)
Shares withheld in lieu of employee tax withholding	(611)	(1,147)
Dividends paid	(6,028)	(5,988)
Net cash used in financing activities	(7,039)	(7,535)
Net increase in cash, cash equivalents and restricted cash	3,056	23,768
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(1,124)	(491)
Cash, cash equivalents and restricted cash at beginning of period	118,639	61,725
Cash, cash equivalents and restricted cash at end of period	$ 120,571	$ 85,002