Condensed Financial Information of Registrant (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Current assets
Cash and cash equivalents	$ 108,091	$ 86,789	$ 61,062	$ 195,160
Prepaid expenses and other current assets	26,848	26,654
Total current assets	301,519	303,775
Deferred charges and other assets, net	9,405	10,291
Total assets	639,347	630,487
Current liabilities
Total current liabilities	228,329	210,794
Long-term debt	124,357	124,263
Other long-term liabilities	18,080	22,797
Total partners' capital	260,145	272,633	279,911	306,334
Total liabilities and partners' capital	639,347	630,487
STAR GAS PARTNERS, L.P. [Member]
Current assets
Cash and cash equivalents	317	294	230	46
Prepaid expenses and other current assets	268	522
Total current assets	585	816
Investment in subsidiaries	387,799	400,048
Deferred charges and other assets, net	2,997	3,328
Total assets	391,381	404,192
Current liabilities
Accrued expenses	4,706	4,969
Total current liabilities	4,706	4,969
Long-term debt	124,357	124,263
Other long-term liabilities	2,173	2,327
Total partners' capital	260,145	272,633
Total liabilities and partners' capital	$ 391,381	$ 404,192