Note 12 - Other Financial Data - Balance Sheet Information (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Accounts receivable	$ 56,130	$ 40,485
Less allowance for doubtful accounts	(298)	(201)
Total	55,832	40,284
Raw materials	28,120	51,808
Work in process	4,519	2,637
Finished goods	22,112	27,408
Total	54,751	81,853
Prepaid insurance	3,620	3,796
Income tax receivable		925
Other	1,455	1,228
Total	5,075	5,949
Cash surrender value of life insurance policies	9,593	9,026
Capitalized financing costs, net	57	105
Other	128	203
Total	9,778	9,334
Land and land improvements	14,421	12,177
Buildings	54,333	50,373
Machinery and equipment	159,423	153,484
Construction in progress	5,122	5,641
Property, plant and equipment, gross	233,299	221,675
Less accumulated depreciation	(130,510)	(123,005)
Total	102,789	98,670
Salaries, wages and related expenses	5,321	5,520
Income taxes	1,520
Customer rebates	1,321	1,015
Property taxes	1,033	1,384
Workers' compensation	115	116
Other	707	632
Total	10,017	8,667
Deferred compensation	10,820	9,276
Deferred Tax Liabilities, Net, Noncurrent	5,782	8,103
Total	$ 16,602	$ 17,379