Receivables (Details) (USD $) In Thousands, unless otherwise specified							3 Months Ended	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Trade Accounts Receivable [Member]	Sep. 30, 2012 Trade Accounts Receivable [Member]	Sep. 30, 2013 Vendor Rebates and Programs [Member]	Sep. 30, 2012 Vendor Rebates and Programs [Member]	Dec. 31, 2012 Accounts Receivable [Member] Customer Concentration Risk [Member]	Sep. 30, 2013 Accounts Receivable [Member] Customer Concentration Risk [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables, gross	$ 309,906	$ 291,668	$ 282,923	$ 271,199	$ 26,983	$ 20,469
Allowance for doubtful accounts	(2,461)	(2,746)
Receivables, net	$ 307,445	$ 288,922
Customer Concentration Risk							7.60%	2.60%