Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Condensed Consolidated Statements of Operations [Abstract]
Revenues	$ 142,135	$ 138,880	$ 392,407	$ 416,931
Cost of goods sold	118,637	100,636	317,401	304,337
Gross profit	23,498	38,244	75,006	112,594
Selling, general and administrative expenses	19,410	21,084	61,876	62,821
Amortization of intangible assets	1,237	1,132	3,658	3,193
Operating income	2,851	16,028	9,472	46,580
Other income			(1,229)
Interest expense	88	228	296	638
Interest income	(66)	(49)	(173)	(206)
Income before income taxes	2,829	15,849	10,578	46,148
Income tax provision	1,122	5,530	3,940	16,199
Net income	1,707	10,319	6,638	29,949
Net income attributable to noncontrolling interest		(33)		(159)
Net income attributable to Powell Industries, Inc.	$ 1,707	$ 10,286	$ 6,638	$ 29,790
Earnings per share attributable to Powell Industries, Inc.:
Basic	$ 0.15	$ 0.89	$ 0.57	$ 2.59
Diluted	$ 0.14	$ 0.88	$ 0.56	$ 2.56
Weighted average shares:
Basic	11,740	11,556	11,730	11,518
Diluted	11,812	11,679	11,806	11,648