Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2013	May 31, 2012
Income Statement [Abstract]
Sales	$ 121,719	$ 111,283	$ 349,823	$ 322,928
Cost of sales	108,528	99,829	312,373	290,265
Gross margin	13,191	11,454	37,450	32,663
Operating expenses	7,326	6,340	22,269	18,883
Research and development expenses	1,590	1,541	4,356	4,198
Income from operations	4,275	3,573	10,825	9,582
Interest expense	(998)	(2,335)	(3,062)	(7,162)
Other non-operating income (expense), net	146	(2,815)	68	(2,579)
Income (loss) before income taxes	3,423	(1,577)	7,831	(159)
Income tax expense	1,365	3,875	2,875	5,041
Net income (loss)	$ 2,058	$ (5,452)	$ 4,956	$ (5,200)
Weighted average common shares and equivalents outstanding:
Basic	12,395	12,300	12,349	12,292
Diluted	12,670	12,300	12,548	12,292
Earnings (loss) per common share:
Basic earnings (loss) per share	$ 0.17	$ (0.44)	$ 0.40	$ (0.42)
Diluted earnings (loss) per share	$ 0.16	$ (0.44)	$ 0.39	$ (0.42)