CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Revenues:
Product sales	$ 549,487	$ 442,597
Product sales to related party	19,006	15,558
Commissions	4,355	3,746
Total revenues	572,848	461,901
Cost of product sales	495,919	399,387
Gross profit	76,929	62,514
Selling, general and administrative expenses	47,460	38,907
Depreciation and amortization	2,392	2,192
Operating income	27,077	21,415
Other income (expense):
Interest expense	(203)	(183)
Earnings of equity method investees	93	77
Other	204	188
Total other income (expense), net	94	82
Income before taxes	27,171	21,497
Income tax expense	(10,420)	(8,301)
Net income	$ 16,751	$ 13,196
Earnings per common share
Basic	$ 1.32	$ 1.05
Diluted	$ 1.32	$ 1.05
Weighted average common shares outstanding:
Weighted Average Number of Shares Outstanding, Basic	12,665	12,581
Weighted Average Number of Shares Outstanding, Diluted	12,695	12,605