CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Operating Activities:
Net income (loss)	$ 16,660	$ 9,890	$ (7,152)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	10,538	12,032	12,903
Stock-based compensation	3,474	3,839	3,152
Bad debt expense	258	233	111
Deferred income taxes	1,473	820	(2,170)
Gain on amended supply agreement	0	0	(507)
Gain on cash surrender value of life insurance	(506)	0	(240)
Changes in operating assets and liabilities:
Accounts receivable, net	41,969	(20,193)	(37,176)
Contract assets and liabilities, net	12,546	55,333	(14,117)
Inventories	304	(7,989)	(3,023)
Income taxes	720	6,681	996
Prepaid expenses and other current assets	662	(2,626)	(237)
Accounts payable	(15,309)	9,550	8,152
Accrued liabilities	465	1,419	8,859
Other, net	(860)	(230)	1,906
Net cash provided by (used in) operating activities	72,394	68,759	(28,543)
Investing Activities:
Purchases of short-term investments	(18,553)	(5,869)	(22,261)
Maturities of short-term investments	6,146	13,088	35,248
Purchases of property, plant and equipment, net	(5,130)	(4,255)	(4,415)
Proceeds from life insurance policy	0	0	1,861
Net cash provided by (used in) investing activities	(17,537)	2,964	10,433
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)	(400)
Shares withheld in lieu of employee tax withholding	(629)	(1,454)	(712)
Dividends paid	(12,066)	(11,998)	(11,916)
Net cash used in financing activities	(13,095)	(13,852)	(13,028)
Net increase (decrease) in cash, cash equivalents and restricted cash	41,762	57,871	(31,138)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(185)	(957)	(347)
Cash, cash equivalents and restricted cash at beginning of period	118,639	61,725	93,210
Cash, cash equivalents and restricted cash at end of period	$ 160,216	$ 118,639	$ 61,725