CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Revenues:
Product sales	$ 1,996,294	$ 1,489,500	$ 1,169,545
Product sales to related party	61,873	55,185	43,017
Commissions	16,979	20,655	16,780
Total revenues	2,075,146	1,565,340	1,229,342
Cost of product sales	1,808,230	1,359,755	1,064,339
Gross profit	266,916	205,585	165,003
Selling, general and administrative expenses	172,104	130,656	105,793
Depreciation and amortization	9,045	6,263	4,992
Operating income	85,767	68,666	54,218
Other income (expense):
Interest expense	(926)	(741)	(539)
Earnings of equity method investees	318	268	220
Other	781	507	427
Total other income (expense), net	173	34	108
Income before taxes	85,940	68,700	54,326
Income tax expense	(32,463)	(26,120)	(20,886)
Net income	$ 53,477	$ 42,580	$ 33,440
Earnings per common share
Basic	$ 4.24	$ 3.42	$ 2.73
Diluted	$ 4.23	$ 3.40	$ 2.70
Weighted average common shares outstanding:
Weighted Average Number of Shares Outstanding, Basic	12,616	12,464	12,241
Weighted Average Number of Shares Outstanding, Diluted	12,647	12,513	12,395