Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Activities:
Net income (loss)	$ (1,128)	$ 5,108
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	6,138	6,518
Amortization	176	174
Stock-based compensation	1,820	3,118
Bad debt expense (recovery)	(97)	339
Deferred income taxes	(243)	337
Gain on amended supply agreement	(1,015)	(1,015)
Changes in operating assets and liabilities:
Accounts receivable, net	34,084	(1,574)
Costs and billings in excess of estimated earnings on uncompleted contracts	(2,074)	11,810
Inventories	6,088	2,653
Prepaid expenses and other current assets	(1,038)	2,133
Accounts payable and income taxes payable	(7,453)	(4,756)
Accrued liabilities	(14,397)	106
Other, net	(1,191)	257
Net cash provided by operating activities	19,670	25,208
Investing Activities:
Proceeds from sale of property, plant and equipment	0	39
Purchases of investments	(14,874)	0
Purchases of property, plant and equipment	(1,702)	(1,126)
Net cash used in investing activities	(16,576)	(1,087)
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)
Shares withheld in lieu of employee tax withholding	(398)	(808)
Purchase of treasury shares	0	(3,740)
Dividends paid	(5,934)	(5,921)
Net cash used in financing activities	(6,732)	(10,869)
Net increase (decrease) in cash and cash equivalents	(3,638)	13,252
Effect of exchange rate changes on cash and cash equivalents	(614)	537
Cash and cash equivalents, beginning of period	97,720	43,569
Cash and cash equivalents, end of period	$ 93,468	$ 57,358